[PATCH] fortran: define $GFC to "yes" if $FC is a GNU compiler

[Stefano Lattarini]

* lib/autoconf/fortran.m4 (AC_PROG_FC): Define `$GFC' to "yes" if
the detected fortran compiler is a GNU compiler, define it to the
empty string otherwise.
This is mostly for consistency for what is done for the C, C++
and Fortran 77 compilers.
* doc/automake.texi: Update.
---
 ChangeLog               |   10 ++++++++++
 doc/autoconf.texi       |    2 ++
 lib/autoconf/fortran.m4 |    5 +++++
 3 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 1bf0196..e51f7d7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,13 @@
+2011-10-21  Stefano Lattarini  <address@hidden>
+
+       fortran: define $GFC to "yes" if $FC is a GNU compiler
+       * lib/autoconf/fortran.m4 (AC_PROG_FC): Define `$GFC' to "yes" if
+       the detected fortran compiler is a GNU compiler, define it to the
+       empty string otherwise.
+       This is mostly for consistency for what is done for the C, C++
+       and Fortran 77 compilers.
+       * doc/automake.texi: Update.
+
 2011-10-13  Eric Blake  <address@hidden>
 
        admin: mention recent copyright assignments
diff --git a/doc/autoconf.texi b/doc/autoconf.texi
index 2ab4599..b6dc67b 100644
--- a/doc/autoconf.texi
+++ b/doc/autoconf.texi
@@ -7931,6 +7931,8 @@ This macro may, alternatively, be invoked with an 
optional first argument
 which, if specified, must be a blank-separated list of Fortran
 compilers to search for, just as in @code{AC_PROG_F77}.
 
+If using @code{gfortran} or @code{g77} (the GNU Fortran compilers), then
+set the shell variable @code{GFC} to @samp{yes}.
 If the output variable @code{FCFLAGS} was not already set in the
 environment, then set it to @option{-g -02} for GNU @code{g77} (or
 @option{-O2} where @code{g77} does not accept @option{-g}).  Otherwise,
diff --git a/lib/autoconf/fortran.m4 b/lib/autoconf/fortran.m4
index 56488a9..e630f27 100644
--- a/lib/autoconf/fortran.m4
+++ b/lib/autoconf/fortran.m4
@@ -382,6 +382,11 @@ AC_ARG_VAR([FCFLAGS], [Fortran compiler flags])dnl
 _AC_ARG_VAR_LDFLAGS()dnl
 _AC_ARG_VAR_LIBS()dnl
 _AC_PROG_FC([$2], [$1])
+if test $ac_compiler_gnu = yes; then
+  GFC=yes
+else
+  GFC=
+fi
 AC_LANG_POP(Fortran)dnl
 ])# AC_PROG_FC
 
-- 
1.7.2.3