AX_F90_MODULE_FLAG: support -module PGI compiler flag

I have "-module " to the list of compiler options that is tried
in order to support the PGI Fortran compiler. Without this
change, the PGI compiler actually accepts "-I" and passes the
test. However, this option is actually meant for setting the
include file search path to find files that are included with the
Fortran INCLUDE statement. Although the -I flag works in this
case because there are no -module options on the command line,
things will not work correctly if the user does bring in the
-module option on the actual compile command line.

1 files changed, 14 insertions, 4 deletions

diff --git a/m4/ax_f90_module_flag.m4 b/m4/ax_f90_module_flag.m4
index 24d463d..9fd8327 100644
--- a/m4/ax_f90_module_flag.m4
+++ b/m4/ax_f90_module_flag.m4
@@ -9,12 +9,22 @@
 #   Find Fortran 90 modules inclusion flag. The module inclusion flag
 #   is stored in the cached variable ax_f90_modflag. An error is
 #   triggered if the flag cannot be found. Supported are the -I GNU
-#   compilers flag, the -M SUN compilers flag, and the -p Absoft Pro
-#   Fortran compiler flag.
+#   compilers flag, the -M SUN compilers flag, the -p flag for Absoft
+#   Pro Fortran compilers, and the -module flag for the PGI Fortran
+#   compiler.
+#
+#   Note that on the PGI compiler the first directory specified with
+#   -module is also the directory where any module files that are
+#   produced will be written out. So if this flag is used and the first
+#   directory specified does not have write permissions, an error will
+#   occur. The most sensible thing to do is is to place
+#   "$(ax_f90_modflag)." on the compile line first to put the current
+#   directory at the front of the list before any other module file
+#   directories.
 #
 # LAST MODIFICATION
 #
-#   2007-05-12
+#   2007-08-04
 #
 # COPYLEFT
 #
@@ -47,7 +57,7 @@ AC_COMPILE_IFELSE([
   ],[],[])
 cd ..
 ax_f90_modflag="not found"
-for ax_flag in "-I " "-M" "-p"; do
+for ax_flag in "-module " "-I " "-M" "-p"; do
   if test "$ax_f90_modflag" = "not found" ; then
     ax_save_FCFLAGS="$FCFLAGS"
     FCFLAGS="$ax_save_FCFLAGS ${ax_flag}tmpdir_$i"