MoonchildProductions#1251 - Part 23: Allow AMD64 build to work.

https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/Build_Instructions/Compiling_32-bit_Firefox_on_a_Linux_64-bit_OS

Setting this up turned out to be easier than I thought it would be. All I had to do was apply these instructions in reverse and add the following to my .mozconfig file:

CC="gcc -m64"
CXX="g++ -m64"
AS="gas --64"
ac_add_options --target=x86_64-pc-solaris2.11
export PKG_CONFIG_PATH=/usr/lib/amd64/pkgconfig
ac_add_options --libdir=/usr/lib/amd64
ac_add_options --x-libraries=/usr/lib/amd64

Most of these changes were fairly trivial, just requiring me to make a few of the changes I made earlier conditional on a 32-bit build. The biggest challenge was figuring out why the JavaScript engine triggered a segfault everytime it tried to allocate memory. But this patch fixes it:

https://github.com/OpenIndiana/oi-userland/blob/oi/hipster/components/web/firefox/patches/patch-js_src_gc_Memory.cpp.patch

Turns out that Solaris on AMD64 handles memory management in a fairly unusual way with a segmented memory model, but it's not that different from what we see on other 64-bit processors. In fact, I saw a SPARC crash for a similar reason, and noticed that it looked just like mine except the numbers in the first segment were reversed. Having played around with hex editors before, I had a feeling I might be dealing with a little-endian version of a big-endian problem, but I didn't expect that knowledge to actually yield an easy solution.

https://bugzilla.mozilla.org/show_bug.cgi?id=577056

https://www.oracle.com/technetwork/server-storage/solaris10/solaris-memory-135224.html

As far as I can tell, this was the last barrier to an AMD64 Solaris build of Pale Moon.

xpcom/reflect/xptcall/md/unix/moz.build

@@ -53,7 +53,7 @@ if CONFIG['OS_ARCH'] == 'SunOS':
     if CONFIG['OS_TEST'] == 'x86_64':
             SOURCES += [
                 'xptcinvoke_asm_x86_64_unix.S',
-                'xptcinvoke_x86_64_unix.cpp',
+                'xptcinvoke_x86_64_solaris.cpp',
                 'xptcstubs_x86_64_linux.cpp'
             ]
     elif '86' in CONFIG['OS_TEST']: