* m4/depend.m4: Grep depcomp's stderr for icc warnings about

ignored options.
* lib/depcomp (icc): New mode.
* tests/depcomp5.test: New file.
* tests/defs.in: Handle required=icc.
* tests/Makefile.am (TESTS): Add it.

1 files changed, 9 insertions, 3 deletions

diff --git a/m4/depend.m4 b/m4/depend.m4
index 4d6ff228e..d0b24dce1 100644
--- a/m4/depend.m4
+++ b/m4/depend.m4
@@ -92,11 +92,17 @@ AC_CACHE_CHECK([dependency style of $depcc],
     if depmode=$depmode \
        source=conftest.c object=conftest.o \
        depfile=conftest.Po tmpdepfile=conftest.TPo \
-       $SHELL ./depcomp $depcc -c -o conftest.o conftest.c >/dev/null 2>&1 &&
+       $SHELL ./depcomp $depcc -c -o conftest.o conftest.c \
+         >/dev/null 2>conftest.err &&
        grep conftest.h conftest.Po > /dev/null 2>&1 &&
        ${MAKE-make} -s -f confmf > /dev/null 2>&1; then
-      am_cv_$1_dependencies_compiler_type=$depmode
-      break
+      # icc doesn't choke on unknown options, it will just issue warnings
+      # (even with -Werror).  So we grep stderr for any message
+      # that says an option was ignored.
+      if grep 'ignoring option' conftest.err >/dev/null 2>&1; then :; else
+        am_cv_$1_dependencies_compiler_type=$depmode
+        break
+      fi
     fi
   done