docs: add note about non-recursive build-sys

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/Documentation/howto-build-sys.txt b/Documentation/howto-build-sys.txt
index 1e774360921178cb82816b08533b61b6d35ef335..cd59e18406820e42ca88202077d3afb476fba178 100644 (file)
--- a/Documentation/howto-build-sys.txt
+++ b/Documentation/howto-build-sys.txt
@@ -1,6 +1,34 @@
 util-linux build system
 =======================
 
+ - the build system is non-recursive, individual subdirectories use
+   Makemodule.am files. These files are merged together by automake
+   into one global Makefile in the top-level directory
+
+ - all final build results (binaries, libtool scripts) are stored in top-level
+   source directory
+
+ - all Makemodule.am files have to be designed as top-level makefiles, it
+   means with full paths (e.g. foo_SOURCES = subdir/foo.c)
+
+ - always use '+=' operator for global variables (e.g. bin_PROGRAMS += foo)
+
+ - use libcommon.la (without path!) for lib/ stuff (e.g. foo_LDADD = libcommon.la)
+
+ - for libblkid, libuuid and libmount use lib<name>.la in _LDADD and
+   -I$(ul_lib<name>_incdir) in _CFLAGS, for example
+
+       foo_LDADD = libmount.la
+       foo_CFLAGS = -I$(ul_libmount_incdir)
+
+ - always use suffixes for hooks, for example
+
+       install-exec-hook-foo:
+               ln -sf foo foooo
+
+       INSTALL_EXEC_HOOKS += install-exec-hook-foo
+
+
  - all util-linux specific autoconf macros use UL_ prefix
 
  - utils in Makefile.am files are enabled/disabled according to BUILD_<NAME>