To allow altoptions.m4 to be shared by both the main Mozilla and the

SpiderMonkey build code, sincluding it shouldn't have any side
effects.  Since only Mozilla wants the side effect, move it to
Mozilla's aclocal.m4.

aclocal.m4

@@ -13,7 +13,10 @@ builtin(include, build/autoconf/libart.m4)dnl
 builtin(include, build/autoconf/pkg.m4)dnl
 builtin(include, build/autoconf/freetype2.m4)dnl
 builtin(include, build/autoconf/codeset.m4)dnl
-dnl
-define(MOZ_TOPSRCDIR,.)dnl MOZ_TOPSRCDIR is used in altoptions.m4
 builtin(include, build/autoconf/altoptions.m4)dnl
 
+# Read the user's .mozconfig script.  We can't do this in
+# configure.in: autoconf puts the argument parsing code above anything
+# expanded from configure.in, and we need to get the configure options
+# from .mozconfig in place before that argument parsing code.
+MOZ_READ_MOZCONFIG(.)

build/autoconf/altoptions.m4

@@ -152,6 +152,3 @@ AC_DEFUN([MOZ_READ_MOZCONFIG],
 # See the mozconfig2configure script for more details.
 _AUTOCONF_TOOLS_DIR=`dirname [$]0`/[$1]/build/autoconf
 . $_AUTOCONF_TOOLS_DIR/mozconfig2configure])
-
-dnl This gets inserted at the top of the configure script
-MOZ_READ_MOZCONFIG(MOZ_TOPSRCDIR)