flex: fix build for nommu systems

The flex binary uses fork() so it breaks on !MMU builds.
Since we usually don't require flex in the target and the common
scenario is that we just want libfl in staging reverse the options so
that BR2_PACKAGE_FLEX just builds and install libfl.a and change the
LIBFL option to BR2_PACKAGE_FLEX_BINARY to install the binary in the
target.

Signed-off-by: Gustavo Zacarias <gustavo@zacarias.com.ar>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/flex/Config.in

@@ -6,10 +6,10 @@ config BR2_PACKAGE_FLEX
 
 	  http://www.gnu.org/software/flex/
 
-config BR2_PACKAGE_FLEX_LIBFL
-	bool "Install libfl.a under staging_dir/usr/lib"
-	default y
+config BR2_PACKAGE_FLEX_BINARY
+	bool "Install tool in the target"
+	# needs fork()
+	depends on BR2_USE_MMU
 	depends on BR2_PACKAGE_FLEX
 	help
-	  Install libfl.a under staging_dir/usr/lib for further development
-	  on a host machine.
+	  Install the flex binary tool in the target filesystem.

package/flex/flex.mk

@@ -16,30 +16,20 @@ FLEX_DEPENDENCIES = \
 # we don't have a host-gettext/libintl
 HOST_FLEX_DEPENDENCIES =
 
+ifeq ($(BR2_PACKAGE_FLEX_BINARY),y)
 # lex -> flex
 define FLEX_INSTALL_LEX
 	cd $(TARGET_DIR)/usr/bin && ln -snf flex lex
 endef
-
-define FLEX_UNINSTALL_LEX
-	-rm $(TARGET_DIR)/usr/bin/lex
-endef
-
 FLEX_POST_INSTALL_HOOKS += FLEX_INSTALL_LEX
-FLEX_POST_CLEAN_HOOKS += FLEX_UNINSTALL_LEX
 
-# libfl installation
-ifeq ($(BR2_PACKAGE_FLEX_LIBFL),y)
-define FLEX_INSTALL_LIBFL
-	install -D $(FLEX_DIR)/libfl.a $(STAGING_DIR)/usr/lib/libfl.a
+else
+
+define FLEX_DISABLE_PROGRAM
+	$(SED) 's/^bin_PROGRAMS.*//' $(@D)/Makefile.in
 endef
+FLEX_POST_PATCH_HOOKS += FLEX_DISABLE_PROGRAM
 
-define FLEX_UNINSTALL_LIBFL
-	-rm $(STAGING_DIR)/lib/libfl.a
-endef
-
-FLEX_POST_INSTALL_HOOKS += FLEX_INSTALL_LIBFL
-FLEX_POST_CLEAN_HOOKS += FLEX_UNINSTALL_LIBFL
 endif
 
 $(eval $(autotools-package))