[svn-r6997] Due to changes in the autoconf macros, the PAC macro to select the...

[svn-r6997] Due to changes in the autoconf macros, the PAC macro to select the compilers to use with MPI programs required multiple changes, as autoconf would prematurely run AC_PROG_CC.  These factor the MPI checks into provide AC_ARG options, select compilers, and check libraries

confdb/aclocal_f77.m4

@@ -682,6 +682,9 @@ EOF
 	# Check that cross != yes so that this works with autoconf 2.52
 	# Check that cross_compiling != yes so that this works with 
 	# autoconf 2.6x for some (but almost certainly not all)x
+	# Question: why do we test that this runs?  It looks like we
+	# needed this for some old Fortran compilers that produced
+	# executable code that then did not run.
 	if test "$ac_cv_prog_f77_cross" != "yes" -a \
 	        "$cross_compiling" != "yes" ; then
 	    if ./conftest >/dev/null 2>&1 ; then

confdb/aclocal_mpi.m4

@@ -85,15 +85,39 @@ dnl created with mpcc will not run locally, but executables created
 dnl with xlc may be used to discover properties of the compiler, such as
 dnl the size of data types).
 dnl
+dnl Historical note:
+dnl Some common autoconf tests, such as AC_CHECK_SIZEOF, used to require
+dnl running a program.  But some MPI compilers (often really compilation 
+dnl scripts) produced programs that could only be run with special commands,
+dnl such as a batch submission system.  To allow these test programs to be
+dnl run, a separate set of compiler variables, TESTCC, TESTF77, etc., 
+dnl were defined.  However, in later versions of autoconf, it both became
+dnl unnecessary to run programs for tests such as AC_CHECK_SIZEOF and 
+dnl it became necessary to define CC etc. before invoking AC_PROG_CC (and
+dnl the othe language compilers), because those commands now do much, much
+dnl more than just determining the compiler.
+dnl
+dnl To address the change, we still define the TESTCC ect. compilers where
+dnl possible to allow the use of AC_TRY_RUN when required, but we define
+dnl the CC etc variables and do not define ac_cv_prog_CC etc., as these 
+dnl cause autoconf to skip all of the other initialization code that 
+dnl AC_PROG_CC etc. runs.  Note also that this command must occur before 
+dnl AC_PROG_CC (or anything that might cause AC_PROG_CC to be invoked).
+dnl
 dnl See also:
 dnl PAC_LANG_PUSH_COMPILERS, PAC_LIB_MPI
 dnl D*/
 AC_DEFUN([PAC_ARG_MPI_TYPES],[
-AC_PROVIDE([AC_PROG_CC])
-AC_SUBST(CC)
-AC_SUBST(CXX)
-AC_SUBST(F77)
-AC_SUBST(FC)
+PAC_ARG_MPI_KNOWN_TYPES
+PAC_MPI_FIND_COMPILERS
+PAC_MPI_CHECK_MPI_LIB
+])
+dnl
+dnl To keep autoconf from prematurely invoking the compiler check scripts,
+dnl we need a command that first sets the compilers and a separate one
+dnl that makes any necessary checks for libraries
+dnl
+AC_DEFUN([PAC_ARG_MPI_KNOWN_TYPES],[
 AC_ARG_WITH(mpich,
 [--with-mpich=path  - Assume that we are building with MPICH],
 ac_mpi_type=mpich)
@@ -127,6 +151,8 @@ fi
 if test "$ac_mpi_type" = "unknown" -a "$pac_lib_mpi_is_building" = "yes" ; then
     ac_mpi_type="mpich"
 fi
+])
+AC_DEFUN([PAC_MPI_FIND_COMPILERS],[
 # Set defaults
 MPIRUN_NP="-np "
 MPIEXEC_N="-n "
@@ -150,19 +176,15 @@ case $ac_mpi_type in
             AC_PATH_PROG(MPICC,mpicc)
             TESTCC=${CC-cc}
             CC="$MPICC"
-	    ac_cv_prog_CC=$CC
             AC_PATH_PROG(MPIF77,mpif77)
             TESTF77=${F77-f77}
             F77="$MPIF77"
-            ac_cv_prog_F77=$F77
             AC_PATH_PROG(MPIFC,mpif90)
             TESTFC=${FC-f90}
             FC="$MPIFC"
-            ac_cv_prog_FC=$FC
             AC_PATH_PROG(MPICXX,mpiCC)
             TESTCXX=${CXX-CC}
             CXX="$MPICXX"
-            ac_cv_prog_CXX=$CXX
 	    # We may want to restrict this to the path containing mpirun
 	    AC_PATH_PROG(MPIEXEC,mpiexec)
 	    AC_PATH_PROG(MPIRUN,mpirun)
@@ -177,23 +199,6 @@ case $ac_mpi_type in
 	;;
 
         mpichnt)
-        dnl
-        dnl This isn't adequate, but it helps with using MPICH-NT/SDK.gcc
-	save_CFLAGS="$CFLAGS"
-        CFLAGS="$save_CFLAGS -I$with_mpichnt/include"
-        save_CPPFLAGS="$CPPFLAGS"
-        CPPFLAGS="$save_CPPFLAGS -I$with_mpichnt/include"
-        save_LDFLAGS="$LDFLAGS"
-        LDFLAGS="$save_LDFLAGS -L$with_mpichnt/lib"
-        AC_CHECK_LIB(mpich,MPI_Init,found="yes",found="no")
-        if test "$found" = "no" ; then
-          AC_CHECK_LIB(mpich2,MPI_Init,found="yes",found="no")
-        fi
-        if test "$found" = "no" ; then
-          CFLAGS=$save_CFLAGS
-          CPPFLAGS=$save_CPPFLAGS
-          LDFLAGS=$save_LDFLAGS
-        fi
         ;;
 
 	lammpi)
@@ -211,19 +216,15 @@ case $ac_mpi_type in
         AC_PATH_PROG(MPICC,mpicc)
         TESTCC=${CC-cc}
         CC="$MPICC"
-        ac_cv_prog_CC=$CC
         AC_PATH_PROG(MPIF77,mpif77)
         TESTF77=${F77-f77}
         F77="$MPIF77"
-        ac_cv_prog_F77=$F77
         AC_PATH_PROG(MPIFC,mpif90)
         TESTFC=${FC-f90}
         FC="$MPIFC"
-        ac_cv_prog_FC=$FC
         AC_PATH_PROG(MPICXX,mpiCC)
         TESTCXX=${CXX-CC}
         CXX="$MPICXX"
-        ac_cv_prog_CXX=$CXX
 	PATH="$save_PATH"
   	MPILIBNAME="lammpi"
 	MPIBOOT="lamboot"
@@ -238,21 +239,26 @@ case $ac_mpi_type in
 	    AC_MSG_ERROR([Could not find IBM MPI compilation scripts.  Either mpcc or mpxlf is missing])
 	fi
 	TESTCC=${CC-xlC}; TESTF77=${F77-xlf}; CC=mpcc; F77=mpxlf
-        ac_cv_prog_CC=$CC
-        ac_cv_prog_F77=$F77
 	# There is no mpxlf90, but the options langlvl and free can
 	# select the Fortran 90 version of xlf
-	TESTFC=${FC-xlf90}; FC="mpxlf -qlanglvl=90ext -qfree=f90"
+	if test "$enable_f90" != no ; then
+	    AC_CHECK_PROGS(MPIXLF90,mpxlf90)
+	    TESTFC=${FC-xlf90}
+            if test "X$MPIXLF90" != "X" ; then 
+	        FC="mpxlf90"
+	    else
+	    	FC="mpxlf -qlanglvl=90ext -qfree=f90"
+	    fi
+	fi
 	MPILIBNAME=""
+	cross_compiling=yes
+	# Turn off the autoconf version 3 warning message
+	ac_tool_warned=yes
 	;;
 
 	sgimpi)
 	TESTCC=${CC:=cc}; TESTF77=${F77:=f77}; 
 	TESTCXX=${CXX:=CC}; TESTFC=${FC:=f90}
-	AC_CHECK_LIB(mpi,MPI_Init)
-	if test "$ac_cv_lib_mpi_MPI_Init" = "yes" ; then
-	    MPILIBNAME="mpi"
-	fi	
 	MPIRUN=mpirun
 	MPIBOOT=""
 	MPIUNBOOT=""
@@ -260,83 +266,118 @@ case $ac_mpi_type in
 
 	generic)
 	# Find the compilers.  Expect the compilers to be mpicc and mpif77
-	# in $with_mpi/bin
-        PAC_PROG_CC
-	# We only look for the other compilers if there is no
-	# disable for them
-	if test "$enable_f77" != no -a "$enable_fortran" != no ; then
-   	    AC_PROG_F77
-        fi
-	if test "$enable_cxx" != no ; then
-	    AC_PROG_CXX
-	fi
-	if test "$enable_f90" != no ; then
-	    PAC_PROG_FC
-	fi
-	# Set defaults for the TEST versions if not already set
-	if test -z "$TESTCC" ; then 
-	    TESTCC=${CC:=cc}
-        fi
-	if test -z "$TESTF77" ; then 
-  	    TESTF77=${F77:=f77}
-        fi
-	if test -z "$TESTCXX" ; then
-	    TESTCXX=${CXX:=CC}
-        fi
-	if test -z "$TESTFC" ; then
-       	    TESTFC=${FC:=f90}
-	fi
+	# in $with_mpi/bin or $with_mpi
         if test "X$MPICC" = "X" ; then
             if test -x "$with_mpi/bin/mpicc" ; then
                 MPICC=$with_mpi/bin/mpicc
+	    elif test -x "$with_mpi/mpicc" ; then
+	        MPICC=$with_mpi/mpicc
+            fi
+        fi
+        if test "X$MPICXX" = "X" ; then
+            if test -x "$with_mpi/bin/mpicxx" ; then
+                MPICXX=$with_mpi/bin/mpicxx
+	    elif test -x "$with_mpi/mpicxx" ; then
+	        MPICXX=$with_mpi/mpicxx
             fi
         fi
         if test "X$MPIF77" = "X" ; then
             if test -x "$with_mpi/bin/mpif77" ; then
                 MPIF77=$with_mpi/bin/mpif77
+	    elif test -x "$with_mpi/mpif77" ; then
+	        MPIF77=$with_mpi/mpif77
+            fi
+        fi
+        if test "X$MPIF90" = "X" ; then
+            if test -x "$with_mpi/bin/mpif90" ; then
+                MPIF90=$with_mpi/bin/mpif90
+	    elif test -x "$with_mpi/mpif90" ; then
+	        MPIF90=$with_mpi/mpif90
             fi
         fi
         if test "X$MPIEXEC" = "X" ; then
             if test -x "$with_mpi/bin/mpiexec" ; then
                 MPIEXEC=$with_mpi/bin/mpiexec
+	    elif test -x "$with_mpi/mpiexec" ; then
+	        MPIEXEC=$with_mpi/mpiexec
             fi
         fi
         CC=$MPICC
         F77=$MPIF77
-        ac_cv_prog_CC=$CC
-        ac_cv_prog_F77=$F77
+	if test "X$MPICXX" != "X" ; then CXX=$MPICXX ; fi
+	if test "X$MPIF90" !- "X" ; then F90=$MPIF90 ; fi
 	;;
 
 	*)
-	# Find the compilers
-	PAC_PROG_CC
-	# We only look for the other compilers if there is no
-	# disable for them
-	if test "$enable_f77" != no -a "$enable_fortran" != no ; then
-   	    AC_PROG_F77
-        fi
-	if test "$enable_cxx" != no ; then
-	    AC_PROG_CXX
-	fi
-	if test "$enable_f90" != no ; then
-	    PAC_PROG_FC
-	fi
-	# Set defaults for the TEST versions if not already set
-	if test -z "$TESTCC" ; then 
-	    TESTCC=${CC:=cc}
-        fi
-	if test -z "$TESTF77" ; then 
-  	    TESTF77=${F77:=f77}
+	# Use the default choices for the compilers
+	;;
+esac
+# Tell autoconf to determine properties of the compilers (these are the 
+# compilers for MPI programs)
+AC_PROG_CC
+if test "$enable_f77" != no -a "$enable_fortran" != no ; then
+    AC_PROG_F77
+fi
+if test "$enable_cxx" != no ; then
+    AC_PROG_CXX
+fi
+if test "$enable_f90" != no ; then
+    PAC_PROG_FC
+fi
+])
+
+dnl
+dnl This uses the selected CC etc to check for include paths and libraries
+AC_DEFUN([PAC_MPI_CHECK_MPI_LIB],[
+case $ac_mpi_type in
+	mpich)
+	;;
+
+        mpichnt)
+        dnl
+        dnl This isn't adequate, but it helps with using MPICH-NT/SDK.gcc
+	save_CFLAGS="$CFLAGS"
+        CFLAGS="$save_CFLAGS -I$with_mpichnt/include"
+        save_CPPFLAGS="$CPPFLAGS"
+        CPPFLAGS="$save_CPPFLAGS -I$with_mpichnt/include"
+        save_LDFLAGS="$LDFLAGS"
+        LDFLAGS="$save_LDFLAGS -L$with_mpichnt/lib"
+        AC_CHECK_LIB(mpich,MPI_Init,found="yes",found="no")
+        if test "$found" = "no" ; then
+          AC_CHECK_LIB(mpich2,MPI_Init,found="yes",found="no")
         fi
-	if test -z "$TESTCXX" ; then
-	    TESTCXX=${CXX:=CC}
+        if test "$found" = "no" ; then
+          CFLAGS=$save_CFLAGS
+          CPPFLAGS=$save_CPPFLAGS
+          LDFLAGS=$save_LDFLAGS
         fi
-	if test -z "$TESTFC" ; then
-       	    TESTFC=${FC:=f90}
-	fi
+        ;;
+
+	lammpi)
+	;;
+
+	ibmmpi)
+	;;
+
+	sgimpi)
+	AC_CHECK_LIB(mpi,MPI_Init)
+	if test "$ac_cv_lib_mpi_MPI_Init" = "yes" ; then
+	    MPILIBNAME="mpi"
+	fi	
+	;;
+
+	generic)
+	AC_SEARCH_LIBS(MPI_Init,mpi mpich2 mpich)
+	if test "$ac_cv_lib_mpi_MPI_Init" = "yes" ; then
+	    MPILIBNAME="mpi"
+	fi	
+	;;
+
+	*)
 	;;
 esac
 ])
+
 dnl
 dnl/*D
 dnl PAC_MPI_F2C - Determine if MPI has the MPI-2 functions MPI_xxx_f2c and

src/mpi/romio/confdb/aclocal_f77.m4

@@ -682,6 +682,9 @@ EOF
 	# Check that cross != yes so that this works with autoconf 2.52
 	# Check that cross_compiling != yes so that this works with 
 	# autoconf 2.6x for some (but almost certainly not all)x
+	# Question: why do we test that this runs?  It looks like we
+	# needed this for some old Fortran compilers that produced
+	# executable code that then did not run.
 	if test "$ac_cv_prog_f77_cross" != "yes" -a \
 	        "$cross_compiling" != "yes" ; then
 	    if ./conftest >/dev/null 2>&1 ; then

src/mpi/romio/confdb/aclocal_mpi.m4

@@ -85,15 +85,39 @@ dnl created with mpcc will not run locally, but executables created
 dnl with xlc may be used to discover properties of the compiler, such as
 dnl the size of data types).
 dnl
+dnl Historical note:
+dnl Some common autoconf tests, such as AC_CHECK_SIZEOF, used to require
+dnl running a program.  But some MPI compilers (often really compilation 
+dnl scripts) produced programs that could only be run with special commands,
+dnl such as a batch submission system.  To allow these test programs to be
+dnl run, a separate set of compiler variables, TESTCC, TESTF77, etc., 
+dnl were defined.  However, in later versions of autoconf, it both became
+dnl unnecessary to run programs for tests such as AC_CHECK_SIZEOF and 
+dnl it became necessary to define CC etc. before invoking AC_PROG_CC (and
+dnl the othe language compilers), because those commands now do much, much
+dnl more than just determining the compiler.
+dnl
+dnl To address the change, we still define the TESTCC ect. compilers where
+dnl possible to allow the use of AC_TRY_RUN when required, but we define
+dnl the CC etc variables and do not define ac_cv_prog_CC etc., as these 
+dnl cause autoconf to skip all of the other initialization code that 
+dnl AC_PROG_CC etc. runs.  Note also that this command must occur before 
+dnl AC_PROG_CC (or anything that might cause AC_PROG_CC to be invoked).
+dnl
 dnl See also:
 dnl PAC_LANG_PUSH_COMPILERS, PAC_LIB_MPI
 dnl D*/
 AC_DEFUN([PAC_ARG_MPI_TYPES],[
-AC_PROVIDE([AC_PROG_CC])
-AC_SUBST(CC)
-AC_SUBST(CXX)
-AC_SUBST(F77)
-AC_SUBST(FC)
+PAC_ARG_MPI_KNOWN_TYPES
+PAC_MPI_FIND_COMPILERS
+PAC_MPI_CHECK_MPI_LIB
+])
+dnl
+dnl To keep autoconf from prematurely invoking the compiler check scripts,
+dnl we need a command that first sets the compilers and a separate one
+dnl that makes any necessary checks for libraries
+dnl
+AC_DEFUN([PAC_ARG_MPI_KNOWN_TYPES],[
 AC_ARG_WITH(mpich,
 [--with-mpich=path  - Assume that we are building with MPICH],
 ac_mpi_type=mpich)
@@ -127,6 +151,8 @@ fi
 if test "$ac_mpi_type" = "unknown" -a "$pac_lib_mpi_is_building" = "yes" ; then
     ac_mpi_type="mpich"
 fi
+])
+AC_DEFUN([PAC_MPI_FIND_COMPILERS],[
 # Set defaults
 MPIRUN_NP="-np "
 MPIEXEC_N="-n "
@@ -150,19 +176,15 @@ case $ac_mpi_type in
             AC_PATH_PROG(MPICC,mpicc)
             TESTCC=${CC-cc}
             CC="$MPICC"
-	    ac_cv_prog_CC=$CC
             AC_PATH_PROG(MPIF77,mpif77)
             TESTF77=${F77-f77}
             F77="$MPIF77"
-            ac_cv_prog_F77=$F77
             AC_PATH_PROG(MPIFC,mpif90)
             TESTFC=${FC-f90}
             FC="$MPIFC"
-            ac_cv_prog_FC=$FC
             AC_PATH_PROG(MPICXX,mpiCC)
             TESTCXX=${CXX-CC}
             CXX="$MPICXX"
-            ac_cv_prog_CXX=$CXX
 	    # We may want to restrict this to the path containing mpirun
 	    AC_PATH_PROG(MPIEXEC,mpiexec)
 	    AC_PATH_PROG(MPIRUN,mpirun)
@@ -177,23 +199,6 @@ case $ac_mpi_type in
 	;;
 
         mpichnt)
-        dnl
-        dnl This isn't adequate, but it helps with using MPICH-NT/SDK.gcc
-	save_CFLAGS="$CFLAGS"
-        CFLAGS="$save_CFLAGS -I$with_mpichnt/include"
-        save_CPPFLAGS="$CPPFLAGS"
-        CPPFLAGS="$save_CPPFLAGS -I$with_mpichnt/include"
-        save_LDFLAGS="$LDFLAGS"
-        LDFLAGS="$save_LDFLAGS -L$with_mpichnt/lib"
-        AC_CHECK_LIB(mpich,MPI_Init,found="yes",found="no")
-        if test "$found" = "no" ; then
-          AC_CHECK_LIB(mpich2,MPI_Init,found="yes",found="no")
-        fi
-        if test "$found" = "no" ; then
-          CFLAGS=$save_CFLAGS
-          CPPFLAGS=$save_CPPFLAGS
-          LDFLAGS=$save_LDFLAGS
-        fi
         ;;
 
 	lammpi)
@@ -211,19 +216,15 @@ case $ac_mpi_type in
         AC_PATH_PROG(MPICC,mpicc)
         TESTCC=${CC-cc}
         CC="$MPICC"
-        ac_cv_prog_CC=$CC
         AC_PATH_PROG(MPIF77,mpif77)
         TESTF77=${F77-f77}
         F77="$MPIF77"
-        ac_cv_prog_F77=$F77
         AC_PATH_PROG(MPIFC,mpif90)
         TESTFC=${FC-f90}
         FC="$MPIFC"
-        ac_cv_prog_FC=$FC
         AC_PATH_PROG(MPICXX,mpiCC)
         TESTCXX=${CXX-CC}
         CXX="$MPICXX"
-        ac_cv_prog_CXX=$CXX
 	PATH="$save_PATH"
   	MPILIBNAME="lammpi"
 	MPIBOOT="lamboot"
@@ -238,21 +239,26 @@ case $ac_mpi_type in
 	    AC_MSG_ERROR([Could not find IBM MPI compilation scripts.  Either mpcc or mpxlf is missing])
 	fi
 	TESTCC=${CC-xlC}; TESTF77=${F77-xlf}; CC=mpcc; F77=mpxlf
-        ac_cv_prog_CC=$CC
-        ac_cv_prog_F77=$F77
 	# There is no mpxlf90, but the options langlvl and free can
 	# select the Fortran 90 version of xlf
-	TESTFC=${FC-xlf90}; FC="mpxlf -qlanglvl=90ext -qfree=f90"
+	if test "$enable_f90" != no ; then
+	    AC_CHECK_PROGS(MPIXLF90,mpxlf90)
+	    TESTFC=${FC-xlf90}
+            if test "X$MPIXLF90" != "X" ; then 
+	        FC="mpxlf90"
+	    else
+	    	FC="mpxlf -qlanglvl=90ext -qfree=f90"
+	    fi
+	fi
 	MPILIBNAME=""
+	cross_compiling=yes
+	# Turn off the autoconf version 3 warning message
+	ac_tool_warned=yes
 	;;
 
 	sgimpi)
 	TESTCC=${CC:=cc}; TESTF77=${F77:=f77}; 
 	TESTCXX=${CXX:=CC}; TESTFC=${FC:=f90}
-	AC_CHECK_LIB(mpi,MPI_Init)
-	if test "$ac_cv_lib_mpi_MPI_Init" = "yes" ; then
-	    MPILIBNAME="mpi"
-	fi	
 	MPIRUN=mpirun
 	MPIBOOT=""
 	MPIUNBOOT=""
@@ -260,83 +266,118 @@ case $ac_mpi_type in
 
 	generic)
 	# Find the compilers.  Expect the compilers to be mpicc and mpif77
-	# in $with_mpi/bin
-        PAC_PROG_CC
-	# We only look for the other compilers if there is no
-	# disable for them
-	if test "$enable_f77" != no -a "$enable_fortran" != no ; then
-   	    AC_PROG_F77
-        fi
-	if test "$enable_cxx" != no ; then
-	    AC_PROG_CXX
-	fi
-	if test "$enable_f90" != no ; then
-	    PAC_PROG_FC
-	fi
-	# Set defaults for the TEST versions if not already set
-	if test -z "$TESTCC" ; then 
-	    TESTCC=${CC:=cc}
-        fi
-	if test -z "$TESTF77" ; then 
-  	    TESTF77=${F77:=f77}
-        fi
-	if test -z "$TESTCXX" ; then
-	    TESTCXX=${CXX:=CC}
-        fi
-	if test -z "$TESTFC" ; then
-       	    TESTFC=${FC:=f90}
-	fi
+	# in $with_mpi/bin or $with_mpi
         if test "X$MPICC" = "X" ; then
             if test -x "$with_mpi/bin/mpicc" ; then
                 MPICC=$with_mpi/bin/mpicc
+	    elif test -x "$with_mpi/mpicc" ; then
+	        MPICC=$with_mpi/mpicc
+            fi
+        fi
+        if test "X$MPICXX" = "X" ; then
+            if test -x "$with_mpi/bin/mpicxx" ; then
+                MPICXX=$with_mpi/bin/mpicxx
+	    elif test -x "$with_mpi/mpicxx" ; then
+	        MPICXX=$with_mpi/mpicxx
             fi
         fi
         if test "X$MPIF77" = "X" ; then
             if test -x "$with_mpi/bin/mpif77" ; then
                 MPIF77=$with_mpi/bin/mpif77
+	    elif test -x "$with_mpi/mpif77" ; then
+	        MPIF77=$with_mpi/mpif77
+            fi
+        fi
+        if test "X$MPIF90" = "X" ; then
+            if test -x "$with_mpi/bin/mpif90" ; then
+                MPIF90=$with_mpi/bin/mpif90
+	    elif test -x "$with_mpi/mpif90" ; then
+	        MPIF90=$with_mpi/mpif90
             fi
         fi
         if test "X$MPIEXEC" = "X" ; then
             if test -x "$with_mpi/bin/mpiexec" ; then
                 MPIEXEC=$with_mpi/bin/mpiexec
+	    elif test -x "$with_mpi/mpiexec" ; then
+	        MPIEXEC=$with_mpi/mpiexec
             fi
         fi
         CC=$MPICC
         F77=$MPIF77
-        ac_cv_prog_CC=$CC
-        ac_cv_prog_F77=$F77
+	if test "X$MPICXX" != "X" ; then CXX=$MPICXX ; fi
+	if test "X$MPIF90" !- "X" ; then F90=$MPIF90 ; fi
 	;;
 
 	*)
-	# Find the compilers
-	PAC_PROG_CC
-	# We only look for the other compilers if there is no
-	# disable for them
-	if test "$enable_f77" != no -a "$enable_fortran" != no ; then
-   	    AC_PROG_F77
-        fi
-	if test "$enable_cxx" != no ; then
-	    AC_PROG_CXX
-	fi
-	if test "$enable_f90" != no ; then
-	    PAC_PROG_FC
-	fi
-	# Set defaults for the TEST versions if not already set
-	if test -z "$TESTCC" ; then 
-	    TESTCC=${CC:=cc}
-        fi
-	if test -z "$TESTF77" ; then 
-  	    TESTF77=${F77:=f77}
+	# Use the default choices for the compilers
+	;;
+esac
+# Tell autoconf to determine properties of the compilers (these are the 
+# compilers for MPI programs)
+AC_PROG_CC
+if test "$enable_f77" != no -a "$enable_fortran" != no ; then
+    AC_PROG_F77
+fi
+if test "$enable_cxx" != no ; then
+    AC_PROG_CXX
+fi
+if test "$enable_f90" != no ; then
+    PAC_PROG_FC
+fi
+])
+
+dnl
+dnl This uses the selected CC etc to check for include paths and libraries
+AC_DEFUN([PAC_MPI_CHECK_MPI_LIB],[
+case $ac_mpi_type in
+	mpich)
+	;;
+
+        mpichnt)
+        dnl
+        dnl This isn't adequate, but it helps with using MPICH-NT/SDK.gcc
+	save_CFLAGS="$CFLAGS"
+        CFLAGS="$save_CFLAGS -I$with_mpichnt/include"
+        save_CPPFLAGS="$CPPFLAGS"
+        CPPFLAGS="$save_CPPFLAGS -I$with_mpichnt/include"
+        save_LDFLAGS="$LDFLAGS"
+        LDFLAGS="$save_LDFLAGS -L$with_mpichnt/lib"
+        AC_CHECK_LIB(mpich,MPI_Init,found="yes",found="no")
+        if test "$found" = "no" ; then
+          AC_CHECK_LIB(mpich2,MPI_Init,found="yes",found="no")
         fi
-	if test -z "$TESTCXX" ; then
-	    TESTCXX=${CXX:=CC}
+        if test "$found" = "no" ; then
+          CFLAGS=$save_CFLAGS
+          CPPFLAGS=$save_CPPFLAGS
+          LDFLAGS=$save_LDFLAGS
         fi
-	if test -z "$TESTFC" ; then
-       	    TESTFC=${FC:=f90}
-	fi
+        ;;
+
+	lammpi)
+	;;
+
+	ibmmpi)
+	;;
+
+	sgimpi)
+	AC_CHECK_LIB(mpi,MPI_Init)
+	if test "$ac_cv_lib_mpi_MPI_Init" = "yes" ; then
+	    MPILIBNAME="mpi"
+	fi	
+	;;
+
+	generic)
+	AC_SEARCH_LIBS(MPI_Init,mpi mpich2 mpich)
+	if test "$ac_cv_lib_mpi_MPI_Init" = "yes" ; then
+	    MPILIBNAME="mpi"
+	fi	
+	;;
+
+	*)
 	;;
 esac