add libpseudotalloc as super-simplistic talloc replacement

In tightly embedded builds (--enable-embedded), we want the ability to
replace talloc with a very simple heap allocator to avoid the complexity
of talloc without modifying all our code that assumes talloc.

This will break the hierarchical notion of the allocator, but
libosmo{core,gsm,coding,codec} don't rely on that anyway.

Change-Id: Ie341034076f242a813f081919dd09d845775ad35
diff --git a/Makefile.am b/Makefile.am
index 6ef275f..3f6df9b 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,7 +1,7 @@
 ACLOCAL_AMFLAGS = -I m4
 
 AM_CPPFLAGS = $(all_includes) -I$(top_srcdir)/include
-SUBDIRS = include src src/vty src/codec src/gsm src/coding src/gb src/ctrl src/sim utils tests
+SUBDIRS = include src src/vty src/codec src/gsm src/coding src/gb src/ctrl src/sim src/pseudotalloc utils tests
 
 pkgconfigdir = $(libdir)/pkgconfig
 pkgconfig_DATA = libosmocore.pc libosmocodec.pc libosmovty.pc libosmogsm.pc \