[Mesa-dev] [PATCH] configure.ac: add and use AC_PROG_BISON/FLEX macros

[Matt Turner]

Defining these macros lets us use AC_PROG_YACC/LEX which makes automake
easier while still specifically requiring bison and flex.

Based on bison.m4 and flex.m4 found in LLVM's tree.

Signed-off-by: Matt Turner <mattst88 at gmail.com>
---
 configure.ac |    9 ++++-----
 m4/bison.m4  |   16 ++++++++++++++++
 m4/flex.m4   |   16 ++++++++++++++++
 3 files changed, 36 insertions(+), 5 deletions(-)
 create mode 100644 m4/bison.m4
 create mode 100644 m4/flex.m4

diff --git a/configure.ac b/configure.ac
index 511d147..c0abeb9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -45,11 +45,10 @@ if test "x$MKDEP" = "x"; then
     AC_MSG_ERROR([makedepend is required to build Mesa])
 fi
 
-AC_PATH_PROG([FLEX], [flex])
-test "x$FLEX" = "x" && AC_MSG_ERROR([flex is needed to build Mesa])
-
-AC_PATH_PROG([BISON], [bison])
-test "x$BISON" = "x" && AC_MSG_ERROR([bison is needed to build Mesa])
+m4_include([m4/bison.m4])
+AC_PROG_BISON
+m4_include([m4/flex.m4])
+AC_PROG_FLEX
 
 dnl Our fallback install-sh is a symlink to minstall. Use the existing
 dnl configuration in that case.
diff --git a/m4/bison.m4 b/m4/bison.m4
new file mode 100644
index 0000000..641d438
--- /dev/null
+++ b/m4/bison.m4
@@ -0,0 +1,16 @@
+#
+# Check for Bison.
+#
+# This macro verifies that Bison is installed.  If successful, then
+# 1) YACC is set to bison -y (to emulate YACC calls)
+# 2) BISON is set to bison
+#
+AC_DEFUN([AC_PROG_BISON],
+[AC_PROG_YACC()
+if test "$YACC" != "bison -y"; then
+  AC_SUBST(BISON,[])
+  AC_MSG_WARN([bison not found])
+else
+  AC_SUBST(BISON,[bison])
+fi
+])
diff --git a/m4/flex.m4 b/m4/flex.m4
new file mode 100644
index 0000000..6a2a004
--- /dev/null
+++ b/m4/flex.m4
@@ -0,0 +1,16 @@
+#
+# Check for FLEX.
+#
+# This macro verifies that flex is installed.  If successful, then
+# 1) LEX is set to flex (to emulate lex calls)
+# 2) FLEX is set to flex
+#
+AC_DEFUN([AC_PROG_FLEX],
+[AC_PROG_LEX()
+if test "$LEX" != "flex"; then
+  AC_SUBST(FLEX,[])
+  AC_MSG_ERROR([flex not found])
+else
+  AC_SUBST(FLEX,[flex])
+fi
+])
-- 
1.7.3.4