Keep one copy of zlib in the SourcePawn tree.

sourcepawn/vm/AMBuilder

@@ -4,6 +4,7 @@ import os
 Includes = [
   os.path.join(SM.mms_root, 'core', 'sourcehook'),
   os.path.join(builder.sourcePath, 'sourcepawn', 'vm'),
+  os.path.join(builder.sourcePath, 'sourcepawn', 'third_party'),
   os.path.join(builder.sourcePath, 'public'),
   os.path.join(builder.sourcePath, 'public', 'sourcepawn'),
   os.path.join(builder.sourcePath, 'public', 'amtl'),
@@ -38,6 +39,7 @@ library.sources += [
   'compiled-function.cpp',
   'environment.cpp',
   'file-utils.cpp',
+  'md5/md5.cpp',
   'opcodes.cpp',
   'plugin-context.cpp',
   'plugin-runtime.cpp',
@@ -48,19 +50,18 @@ library.sources += [
   'x86/code-stubs-x86.cpp',
   'x86/jit_x86.cpp',
   'x86/x86-utils.cpp',
-  'zlib/adler32.c',
-  'zlib/compress.c',
-  'zlib/crc32.c',
-  'zlib/deflate.c',
-  'zlib/gzio.c',
-  'zlib/infback.c',
-  'zlib/inffast.c',
-  'zlib/inflate.c',
-  'zlib/inftrees.c',
-  'zlib/trees.c',
-  'zlib/uncompr.c',
-  'zlib/zutil.c',
-  'md5/md5.cpp',
+  '../third_party/zlib/adler32.c',
+  '../third_party/zlib/compress.c',
+  '../third_party/zlib/crc32.c',
+  '../third_party/zlib/deflate.c',
+  '../third_party/zlib/gzio.c',
+  '../third_party/zlib/infback.c',
+  '../third_party/zlib/inffast.c',
+  '../third_party/zlib/inflate.c',
+  '../third_party/zlib/inftrees.c',
+  '../third_party/zlib/trees.c',
+  '../third_party/zlib/uncompr.c',
+  '../third_party/zlib/zutil.c',
   '../../public/jit/x86/assembler-x86.cpp',
 ]
 libsourcepawn = builder.Add(library).binary