Document that GNU make is required

In theory the Autotools build system supports any "make" implementation,
but there are no regular contributors who test with BSD make, so the
inevitable result is that only GNU make actually works (fd.o #48277).

Apparently there's only one GNUism at the moment, which is fixable,
but that means repeating ourselves a bit more. If we instead document
that GNU make is required, we can simplify the Makefiles over time
by using extensions like $(patsubst), leading to a less error-prone
build system.

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=48277
Signed-off-by: Simon McVittie <simon.mcvittie@collabora.co.uk>
Reviewed-by: Chengwei Yang <chengwei.yang@intel.com>

diff --git a/README b/README
index fd832ca..aea8330 100644 (file)
--- a/README
+++ b/README
@@ -66,7 +66,9 @@ Configuration
 dbus could be build by using autotools or cmake. 
 
 When using autotools the configure step is initiated by running ./configure 
-with or without additional configuration flags. 
+with or without additional configuration flags. dbus requires GNU Make
+(on BSD systems, this is typically called gmake) or a "make" implementation
+with compatible extensions.
 
 When using cmake the configure step is initiated by running the cmake 
 program with or without additional configuration flags.