From: Jory A. Pratt <anarchy@gentoo.org>

Install application into $(MOZ_APP_NAME) instead of the upstream default
of $(MOZ_APP_NAME)-$(MOZ_APP_VERSION)

diff --git a/config/baseconfig.mk b/config/baseconfig.mk
--- a/config/baseconfig.mk
+++ b/config/baseconfig.mk
@@ -1,16 +1,16 @@
 # This file is normally included by autoconf.mk, but it is also used
 # directly in python/mozbuild/mozbuild/base.py for gmake validation.
 # We thus use INCLUDED_AUTOCONF_MK to enable/disable some parts depending
 # whether a normal build is happening or whether the check is running.
-includedir := $(includedir)/$(MOZ_APP_NAME)-$(MOZ_APP_VERSION)
-idldir = $(datadir)/idl/$(MOZ_APP_NAME)-$(MOZ_APP_VERSION)
-installdir = $(libdir)/$(MOZ_APP_NAME)-$(MOZ_APP_VERSION)
-sdkdir = $(libdir)/$(MOZ_APP_NAME)-devel-$(MOZ_APP_VERSION)
+includedir := $(includedir)/$(MOZ_APP_NAME)
+idldir = $(includedir)/idl/$(MOZ_APP_NAME)
+installdir = $(libdir)/$(MOZ_APP_NAME)
+sdkdir = $(libdir)/$(MOZ_APP_NAME)
 ifeq (.,$(DEPTH))
 DIST = dist
 else
 DIST = $(DEPTH)/dist
 endif
 ABS_DIST = $(topobjdir)/dist
 
 # We do magic with OBJ_SUFFIX in config.mk, the following ensures we don't