From 732056e3d3a35fad43515d5d7a87dc8572ae097e Mon Sep 17 00:00:00 2001
From: David Sterba <dsterba@suse.com>
Date: Mon, 30 Jan 2017 11:04:16 +0100
Subject: [PATCH] btrfs-progs: build: split makefile to generated and stable
 parts

It's not really necessary to configure and regenerate Makefiles in cases
like adding a new source file. The build environment and optional
features are not affected by that.

Signed-off-by: David Sterba <dsterba@suse.com>
---
 .gitignore              |  2 +-
 Makefile.in => Makefile | 35 +++++++++--------------------------
 Makefile.inc.in         | 36 ++++++++++++++++++++++++++++++++++++
 configure.ac            |  2 +-
 4 files changed, 47 insertions(+), 28 deletions(-)
 rename Makefile.in => Makefile (96%)
 create mode 100644 Makefile.inc.in

diff --git a/.gitignore b/.gitignore
index 98b3657b..7d4404c2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -67,7 +67,7 @@ cscope.out
 .clang_complete
 depcomp
 libtool
-Makefile
+Makefile.inc
 Documentation/Makefile
 missing
 mkinstalldirs
diff --git a/Makefile.in b/Makefile
similarity index 96%
rename from Makefile.in
rename to Makefile
index 3813c994..18e4e82b 100644
--- a/Makefile.in
+++ b/Makefile
@@ -37,19 +37,15 @@
 # Export all variables to sub-makes by default
 export
 
-include Makefile.extrawarn
+-include Makefile.inc
+ifneq ($(MAKEFILE_INC_INCLUDED),yes)
+$(error Makefile.inc not generated, please configure first)
+endif
 
-CC = @CC@
-LN_S = @LN_S@
-AR = @AR@
-RM = @RM@
-RMDIR = @RMDIR@
-INSTALL = @INSTALL@
-DISABLE_DOCUMENTATION = @DISABLE_DOCUMENTATION@
-DISABLE_BTRFSCONVERT = @DISABLE_BTRFSCONVERT@
-BTRFSCONVERT_EXT2 = @BTRFSCONVERT_EXT2@
 TAGS_CMD := ctags
 
+include Makefile.extrawarn
+
 EXTRA_CFLAGS :=
 EXTRA_LDFLAGS :=
 
@@ -60,7 +56,7 @@ DEBUG_CFLAGS :=
 TOPDIR := $(shell pwd)
 
 # Common build flags
-CFLAGS = @CFLAGS@ \
+CFLAGS = $(SUBST_CFLAGS) \
 	 -include config.h \
 	 -DBTRFS_FLAT_INCLUDES \
 	 -D_XOPEN_SOURCE=700  \
@@ -72,19 +68,15 @@ CFLAGS = @CFLAGS@ \
 	 $(DEBUG_CFLAGS_INTERNAL) \
 	 $(EXTRA_CFLAGS)
 
-LDFLAGS = @LDFLAGS@ \
+LDFLAGS = $(SUBST_LDFLAGS) \
 	  -rdynamic -L$(TOPDIR) $(EXTRA_LDFLAGS)
 
-LIBS_BASE = @UUID_LIBS@ @BLKID_LIBS@ -L. -pthread
-LIBS_COMP = @ZLIB_LIBS@ @LZO2_LIBS@
 LIBS = $(LIBS_BASE)
 LIBBTRFS_LIBS = $(LIBS_BASE)
 
 # Static compilation flags
 STATIC_CFLAGS = $(CFLAGS) -ffunction-sections -fdata-sections
 STATIC_LDFLAGS = -static -Wl,--gc-sections
-STATIC_LIBS_BASE = @UUID_LIBS_STATIC@ @BLKID_LIBS_STATIC@ -L. -pthread
-STATIC_LIBS_COMP = @ZLIB_LIBS_STATIC@ @LZO2_LIBS_STATIC@
 STATIC_LIBS = $(STATIC_LIBS_BASE)
 
 # don't use FORTIFY with sparse because glibc with FORTIFY can
@@ -124,14 +116,6 @@ TESTS = fsck-tests.sh convert-tests.sh
 
 udev_rules = 64-btrfs-dm.rules
 
-prefix ?= @prefix@
-exec_prefix = @exec_prefix@
-bindir = @bindir@
-libdir ?= @libdir@
-incdir = @includedir@/btrfs
-udevdir = @UDEVDIR@
-udevruledir = ${udevdir}/rules.d
-
 ifeq ("$(origin V)", "command line")
   BUILD_VERBOSE = $(V)
 endif
@@ -201,7 +185,6 @@ endif
 
 # external libs required by various binaries; for btrfs-foo,
 # specify btrfs_foo_libs = <list of libs>; see $($(subst...)) rules below
-btrfs_convert_libs = @EXT2FS_LIBS@ @COM_ERR_LIBS@
 btrfs_convert_cflags = -DBTRFSCONVERT_EXT2=$(BTRFSCONVERT_EXT2)
 btrfs_fragments_libs = -lgd -lpng -ljpeg -lfreetype
 btrfs_debug_tree_objects = cmds-inspect-dump-tree.o
@@ -514,7 +497,7 @@ clean-doc:
 clean-gen:
 	@echo "Cleaning Generated Files"
 	$(Q)$(RM) -rf -- version.h config.status config.cache connfig.log \
-		configure.lineno config.status.lineno Makefile \
+		configure.lineno config.status.lineno Makefile.inc \
 		Documentation/Makefile tags \
 		config.log config.h config.h.in~ aclocal.m4 \
 		configure autom4te.cache/ config/
diff --git a/Makefile.inc.in b/Makefile.inc.in
new file mode 100644
index 00000000..4e1b68cb
--- /dev/null
+++ b/Makefile.inc.in
@@ -0,0 +1,36 @@
+# Variables set during configure phase:
+# * build environment, paths
+# * features (eg. convert, documentation)
+export
+
+CC = @CC@
+LN_S = @LN_S@
+AR = @AR@
+RM = @RM@
+RMDIR = @RMDIR@
+INSTALL = @INSTALL@
+DISABLE_DOCUMENTATION = @DISABLE_DOCUMENTATION@
+DISABLE_BTRFSCONVERT = @DISABLE_BTRFSCONVERT@
+BTRFSCONVERT_EXT2 = @BTRFSCONVERT_EXT2@
+
+SUBST_CFLAGS = @CFLAGS@
+SUBST_LDFLAGS = @LDFLAGS@
+
+LIBS_BASE = @UUID_LIBS@ @BLKID_LIBS@ -L. -pthread
+LIBS_COMP = @ZLIB_LIBS@ @LZO2_LIBS@
+STATIC_LIBS_BASE = @UUID_LIBS_STATIC@ @BLKID_LIBS_STATIC@ -L. -pthread
+STATIC_LIBS_COMP = @ZLIB_LIBS_STATIC@ @LZO2_LIBS_STATIC@
+
+prefix ?= @prefix@
+exec_prefix = @exec_prefix@
+bindir = @bindir@
+libdir ?= @libdir@
+incdir = @includedir@/btrfs
+udevdir = @UDEVDIR@
+udevruledir = ${udevdir}/rules.d
+
+# external libs required by various binaries; for btrfs-foo,
+# specify btrfs_foo_libs = <list of libs>; see $($(subst...)) rules in Makefile
+btrfs_convert_libs = @EXT2FS_LIBS@ @COM_ERR_LIBS@
+
+MAKEFILE_INC_INCLUDED = yes
diff --git a/configure.ac b/configure.ac
index b08bfe60..30055f85 100644
--- a/configure.ac
+++ b/configure.ac
@@ -198,7 +198,7 @@ AC_SUBST([LIBBTRFS_PATCHLEVEL])
 AC_CONFIG_HEADERS([config.h])
 
 AC_CONFIG_FILES([
-Makefile
+Makefile.inc
 Documentation/Makefile
 version.h
 ])