Fix combreloc test with BSD grep

The test for "-z combreloc" fails when cross-compiling on a machine
that uses BSD grep (e.g. on macos). grep complains about empty
subexpression and exits with non-zero status, which is interpreted
by configure as "not found". As a result, support for "-z combreloc"
(HAVE_Z_COMBRELOC) is not detected, leading to link failure on SPARC.

While there, replace fgrep with 'grep -F', as fgrep is non-POSIX.

	* configure.ac: Avoid empty subexpression in grep.

Signed-off-by: Alexey Neyman <stilor@att.net>

3 files changed, 14 insertions, 9 deletions

diff --git a/ChangeLog b/ChangeLog
index 03ea36f08e..47faa520be 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2017-03-15  Alexey Neyman  <stilor@att.net>
+
+	* configure.ac: Avoid empty subexpression in grep.
+	* configure: Regenerate.
+
 2017-03-13  Adhemerval Zanella  <adhemerval.zanella@linaro.org>
 
 	* posix/test-errno.c (do_test): Initialize setsockopt optlen.
diff --git a/configure b/configure
index eecd0ace74..5be4ff611f 100755
--- a/configure
+++ b/configure
@@ -5804,7 +5804,7 @@ if { ac_try='${CC-cc} $CFLAGS $CPPFLAGS $LDFLAGS
   $as_echo "$as_me:${as_lineno-$LINENO}: \$? = $ac_status" >&5
   test $ac_status = 0; }; }
 then
-  if $READELF -S conftest.so | grep '\.rel\(a\|\)\.dyn' > /dev/null; then
+  if $READELF -S conftest.so | grep -E '.rela?.dyn' > /dev/null; then
     libc_cv_z_combreloc=yes
   else
     libc_cv_z_combreloc=no
@@ -6120,7 +6120,7 @@ void zero (void *x)
   __builtin_memset (x, 0, 1000);
 }
 EOF
-if { ac_try='${CC-cc} -O3 -S conftest.c -o - | fgrep "memset" > /dev/null'
+if { ac_try='${CC-cc} -O3 -S conftest.c -o - | grep -F "memset" > /dev/null'
   { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
   (eval $ac_try) 2>&5
   ac_status=$?
@@ -6152,7 +6152,7 @@ char *foo (const char *a, const char *b)
   return __builtin_strstr (a, b);
 }
 EOF
-if { ac_try='${CC-cc} -O3 -S conftest.c -o - | fgrep "my_strstr" > /dev/null'
+if { ac_try='${CC-cc} -O3 -S conftest.c -o - | grep -F "my_strstr" > /dev/null'
   { { eval echo "\"\$as_me\":${as_lineno-$LINENO}: \"$ac_try\""; } >&5
   (eval $ac_try) 2>&5
   ac_status=$?
@@ -6511,7 +6511,7 @@ long ehdr (void) { return __ehdr_start.val; }
 
 _ACEOF
 if ac_fn_c_try_link "$LINENO"; then :
-  if $READELF -r conftest | fgrep __ehdr_start >/dev/null; then
+  if $READELF -r conftest | grep -F __ehdr_start >/dev/null; then
 		  libc_cv_ehdr_start=broken
 		else
 		  libc_cv_ehdr_start=yes
diff --git a/configure.ac b/configure.ac
index 4a77411b71..4981bf9691 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1390,8 +1390,8 @@ dnl The following test is a bit weak.  We must use a tool which can test
 dnl cross-platform since the gcc used can be a cross compiler.  Without
 dnl introducing new options this is not easily doable.  Instead use a tool
 dnl which always is cross-platform: readelf.  To detect whether -z combreloc
-dnl look for a section named .rel.dyn.
-  if $READELF -S conftest.so | grep '\.rel\(a\|\)\.dyn' > /dev/null; then
+dnl look for a section named .rel.dyn or .rela.dyn.
+  if $READELF -S conftest.so | grep -E '.rela?.dyn' > /dev/null; then
     libc_cv_z_combreloc=yes
   else
     libc_cv_z_combreloc=no
@@ -1586,7 +1586,7 @@ void zero (void *x)
 }
 EOF
 dnl
-if AC_TRY_COMMAND([${CC-cc} -O3 -S conftest.c -o - | fgrep "memset" > /dev/null]);
+if AC_TRY_COMMAND([${CC-cc} -O3 -S conftest.c -o - | grep -F "memset" > /dev/null]);
 then
   libc_cv_gcc_builtin_memset=no
 else
@@ -1606,7 +1606,7 @@ char *foo (const char *a, const char *b)
 }
 EOF
 dnl
-if AC_TRY_COMMAND([${CC-cc} -O3 -S conftest.c -o - | fgrep "my_strstr" > /dev/null]);
+if AC_TRY_COMMAND([${CC-cc} -O3 -S conftest.c -o - | grep -F "my_strstr" > /dev/null]);
 then
   libc_cv_gcc_builtin_redirection=yes
 else
@@ -1747,7 +1747,7 @@ typedef struct {
 extern const Ehdr __ehdr_start __attribute__ ((visibility ("hidden")));
 long ehdr (void) { return __ehdr_start.val; }
 ])],
-	       [if $READELF -r conftest | fgrep __ehdr_start >/dev/null; then
+	       [if $READELF -r conftest | grep -F __ehdr_start >/dev/null; then
 		  libc_cv_ehdr_start=broken
 		else
 		  libc_cv_ehdr_start=yes