Elide Fortran-specific tests when no Fortran compiler is available.

configure

@@ -15126,7 +15126,8 @@ ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $
 ac_compiler_gnu=$ac_cv_c_compiler_gnu
-ac_ext=${ac_fc_srcext-f}
+if test -n "$FC" && test "X$FC" != "Xno"; then :
+  ac_ext=${ac_fc_srcext-f}
 ac_compile='$FC -c $FCFLAGS $ac_fcflags_srcext conftest.$ac_ext >&5'
 ac_link='$FC -o conftest$ac_exeext $FCFLAGS $LDFLAGS $ac_fcflags_srcext conftest.$ac_ext $LIBS >&5'
 ac_compiler_gnu=$ac_cv_fc_compiler_gnu
@@ -15177,7 +15178,7 @@ ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
 ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
 ac_compiler_gnu=$ac_cv_c_compiler_gnu
-ac_ext=${ac_fc_srcext-f}
+   ac_ext=${ac_fc_srcext-f}
 ac_compile='$FC -c $FCFLAGS $ac_fcflags_srcext conftest.$ac_ext >&5'
 ac_link='$FC -o conftest$ac_exeext $FCFLAGS $LDFLAGS $ac_fcflags_srcext conftest.$ac_ext $LIBS >&5'
 ac_compiler_gnu=$ac_cv_fc_compiler_gnu
@@ -15911,12 +15912,13 @@ $as_echo "$acx_sl_cv_fc_indirect_ok" >&6; }
-ac_ext=c
+   ac_ext=c
 ac_cpp='$CPP $CPPFLAGS'
 ac_compile='$CC -c $CFLAGS $CPPFLAGS conftest.$ac_ext >&5'
 ac_link='$CC -o conftest$ac_exeext $CFLAGS $CPPFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'
 ac_compiler_gnu=$ac_cv_c_compiler_gnu
+fi
 ac_ext=f
 ac_compile='$F77 -c $FFLAGS conftest.$ac_ext >&5'
 ac_link='$F77 -o conftest$ac_exeext $FFLAGS $LDFLAGS conftest.$ac_ext $LIBS >&5'

configure.ac

@@ -38,10 +38,11 @@ LT_INIT([pic-only])
 AC_CHECK_TOOL([CC],[gcc],[:])
 AC_PROG_CC_C99
 AC_PROG_FC
-AC_FC_SRCEXT([f90])
-AC_LANG_PUSH([Fortran])
-AC_PROG_FPP
-AC_LANG_POP([Fortran])
+AS_IF([test -n "$FC" && test "X$FC" != "Xno"],
+  [AC_FC_SRCEXT([f90])
+   AC_LANG_PUSH([Fortran])
+   AC_PROG_FPP
+   AC_LANG_POP([Fortran])])
 AC_PROG_F77
 AC_PROG_RANLIB
 AC_PROG_CXX