copied from automake-1.1l

1 files changed, 37 insertions, 0 deletions

diff --git a/m4/regex.m4 b/m4/regex.m4
new file mode 100644
index 000000000..007b16636
--- /dev/null
+++ b/m4/regex.m4
@@ -0,0 +1,37 @@
+## --------------------------------- ##
+## Check if --with-regex was given.  ##
+## --------------------------------- ##
+
+# serial 1
+
+# The idea is to distribute rx.[hc] and regex.[hc] together, for a while.
+# The WITH_REGEX symbol (which should also be documented in acconfig.h)
+# is used to decide which of regex.h or rx.h should be included in the
+# application.  If `./configure --with-regex' is given (the default), the
+# package will use gawk's regex.  If `./configure --without-regex', a
+# check is made to see if rx is already installed, as with newer Linux'es.
+# If not found, the package will use the rx from the distribution.
+# If found, the package will use the system's rx which, on Linux at least,
+# will result in a smaller executable file.
+
+AC_DEFUN(AM_WITH_REGEX,
+[AC_MSG_CHECKING(which of GNU rx or gawk's regex is wanted)
+AC_ARG_WITH(regex,
+[  --without-regex         use GNU rx in lieu of gawk's regex for matching],
+[test "$withval" = yes && am_with_regex=1],
+[am_with_regex=1])
+if test -n "$am_with_regex"; then
+  AC_MSG_RESULT(regex)
+  AC_DEFINE(WITH_REGEX)
+  AC_CACHE_CHECK([for GNU regex in libc], am_cv_gnu_regex,
+    AC_TRY_LINK([], [extern int re_max_failures; re_max_failures = 1],
+		am_cv_gnu_regex=yes, am_cv_gnu_regex=no))
+  if test $am_cv_gnu_regex = no; then
+    LIBOBJS="$LIBOBJS regex.o"
+  fi
+else
+  AC_MSG_RESULT(rx)
+  AC_CHECK_FUNC(re_rx_search, , [LIBOBJS="$LIBOBJS rx.o"])
+fi
+AC_SUBST(LIBOBJS)dnl
+])