libbacktrace: replace fgrep with grep in configure script

Patch by Xi Ruoyao.

	* configure.ac: Use grep instead of fgrep.
	* configure: Regenerate.

Author: ianlancetaylor

configure

@@ -12887,7 +12887,7 @@ else
   libbacktrace_cv_objcopy_debuglink=no
 elif ! test -n "${OBJCOPY}"; then
   libbacktrace_cv_objcopy_debuglink=no
-elif ${OBJCOPY} --help | fgrep add-gnu-debuglink >/dev/null 2>&1; then
+elif ${OBJCOPY} --help | grep add-gnu-debuglink >/dev/null 2>&1; then
   libbacktrace_cv_objcopy_debuglink=yes
 else
   libbacktrace_cv_objcopy_debuglink=no

configure.ac

@@ -497,7 +497,7 @@ AC_CACHE_CHECK([whether objcopy supports debuglink],
   libbacktrace_cv_objcopy_debuglink=no
 elif ! test -n "${OBJCOPY}"; then
   libbacktrace_cv_objcopy_debuglink=no
-elif ${OBJCOPY} --help | fgrep add-gnu-debuglink >/dev/null 2>&1; then
+elif ${OBJCOPY} --help | grep add-gnu-debuglink >/dev/null 2>&1; then
   libbacktrace_cv_objcopy_debuglink=yes
 else
   libbacktrace_cv_objcopy_debuglink=no