update pkgconfig for craype 2.x to group libraries

fixes #145

ChangeLog

@@ -15,6 +15,8 @@ darshan-2.3.1-pre1
   darshan-job-summary.pl (reported by Matthieu Dorier)
 * Clean up autoconf test for zlib and make zlib mandatory (reported by Kalyana
   Chadalavada)
+* add --start-group and --end-group notation to Darshan libraries for Cray PE
+  2.x environment to fix link-time corner cases (Yushu Yao)
 
 darshan-2.3.0
 =============

darshan-runtime/lib/pkgconfig/darshan-runtime.pc.in

@@ -14,5 +14,5 @@ darshan_libdir= -L${darshan_prefix}/lib
 darshan_linkopts="-Wl,-u,MPI_Init,-u,MPI_Wtime,-u,__wrap_H5Fcreate,-u,__wrap_ncmpi_create,-wrap,write,-wrap,open,-wrap,creat,-wrap,creat64,-wrap,open64,-wrap,close,-wrap,read,-wrap,lseek,-wrap,lseek64,-wrap,pread,-wrap,pwrite,-wrap,readv,-wrap,writev,-wrap,__xstat,-wrap,__lxstat,-wrap,__fxstat,-wrap,__xstat64,-wrap,__lxstat64,-wrap,__fxstat64,-wrap,mmap,-wrap,mmap64,-wrap,fopen,-wrap,fclose,-wrap,fread,-wrap,fwrite,-wrap,fseek,-wrap,fopen64,-wrap,pread64,-wrap,pwrite64,-wrap,fsync,-wrap,fdatasync,-wrap,ncmpi_create,-wrap,ncmpi_open,-wrap,ncmpi_close,-wrap,H5Fcreate,-wrap,H5Fopen,-wrap,H5Fclose,-wrap,aio_write,-wrap,aio_write64,-wrap,aio_read,-wrap,aio_read64,-wrap,lio_listio,-wrap,lio_listio64,-wrap,aio_return,-wrap,aio_return64,-wrap,mkstemp,-wrap,mkostemp,-wrap,mkstemps,-wrap,mkostemps"
 
 Cflags:
-Libs: ${darshan_linkopts} ${darshan_libdir} -lfmpich -lmpichcxx -ldarshan-mpi-io -ldarshan-posix -ldarshan-stubs
+Libs: ${darshan_linkopts} ${darshan_libdir} -lfmpich -lmpichcxx -Wl,--start-group -ldarshan-mpi-io -ldarshan-posix -ldarshan-stubs -Wl,--end-group
 Libs.private: