I've tried to build pulse audio on OS X 10.8.2 with the following configure options:
./autogen.sh --prefix=/Library/Frameworks/PulseAudio.framework/Contents/MacOS --enable-mac-universal --disable-dependency-tracking --disable-jack --disable-glib2 --disable-hal --disable-bluez --disable-dbus --disable-avahi --with-mac-version-min=10.7 --with-mac-sysroot=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.7.sdk

I've tried to build  it with both gcc and clang, versions from latest Xcode (4.5);

$ clang -v                                                                                                                                                        
Apple clang version 4.1 (tags/Apple/clang-421.11.66) (based on LLVM 3.1svn)
Target: x86_64-apple-darwin12.2.0
Thread model: posix

$ gcc -v                                                                                                                                                          [18:11:42]
Using built-in specs.
Target: i686-apple-darwin11
Configured with: /private/var/tmp/llvmgcc42/llvmgcc42-2336.11~67/src/configure --disable-checking --enable-werror --prefix=/Applications/Xcode.app/Contents/Developer/usr/llvm-gcc-4.2 --mandir=/share/man --enable-languages=c,objc,c++,obj-c++ --program-prefix=llvm- --program-transform-name=/^[cg][^.-]*$/s/$/-4.2/ --with-slibdir=/usr/lib --build=i686-apple-darwin11 --enable-llvm=/private/var/tmp/llvmgcc42/llvmgcc42-2336.11~67/dst-llvmCore/Developer/usr/local --program-prefix=i686-apple-darwin11- --host=x86_64-apple-darwin11 --target=i686-apple-darwin11 --with-gxx-include-dir=/usr/include/c++/4.2.1
Thread model: posix
gcc version 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2336.11.00)


clang output:
CC       libpulsecore_2.98_la-svolume_mmx.lo
pulsecore/svolume_mmx.c:108:43: error: register %rcx is only available in 64-bit mode
        " je 2f                         \n\t"
                                          ^
<inline asm>:5:9: note: instantiated into assembly here
         movd (%rcx, %edi, 4), %mm0      
               ^~~~
pulsecore/svolume_mmx.c:124:43: error: register %rcx is only available in 64-bit mode
        "3:                             \n\t" /* do samples in groups of 2 */
                                          ^
<inline asm>:33:9: note: instantiated into assembly here
         movq (%rcx, %edi, 4), %mm0      
               ^~~~
pulsecore/svolume_mmx.c:137:43: error: register %rcx is only available in 64-bit mode
        "5:                             \n\t" /* do samples in groups of 4 */
                                          ^
<inline asm>:59:9: note: instantiated into assembly here
         movq (%rcx, %edi, 4), %mm0      
               ^~~~
pulsecore/svolume_mmx.c:138:43: error: register %rcx is only available in 64-bit mode
        " movq (%q1, %3, 4), %%mm0      \n\t" /* |  v1h  |  v1l  |  v0h  |  v0l  | */
                                          ^
<inline asm>:60:10: note: instantiated into assembly here
         movq 8(%rcx, %edi, 4), %mm2     
                ^~~~
pulsecore/svolume_mmx.c:181:43: error: register %rcx is only available in 64-bit mode
        " je 2f                         \n\t"
                                          ^
<inline asm>:9:9: note: instantiated into assembly here
         movd (%rcx, %edi, 4), %mm0      
               ^~~~
pulsecore/svolume_mmx.c:199:43: error: register %rcx is only available in 64-bit mode
        "3:                             \n\t" /* do samples in groups of 2 */
                                          ^
<inline asm>:39:9: note: instantiated into assembly here
         movq (%rcx, %edi, 4), %mm0      
               ^~~~
pulsecore/svolume_mmx.c:214:43: error: register %rcx is only available in 64-bit mode
        "5:                             \n\t" /* do samples in groups of 4 */
                                          ^
<inline asm>:73:9: note: instantiated into assembly here
         movq (%rcx, %edi, 4), %mm0      
               ^~~~
pulsecore/svolume_mmx.c:215:43: error: register %rcx is only available in 64-bit mode
        " movq (%q1, %3, 4), %%mm0      \n\t" /* |  v1h  |  v1l  |  v0h  |  v0l  | */
                                          ^
<inline asm>:74:10: note: instantiated into assembly here
         movq 8(%rcx, %edi, 4), %mm2     
                ^~~~
8 errors generated.
make[3]: *** [libpulsecore_2.98_la-svolume_mmx.lo] Error 1
make[2]: *** [install] Error 2
make[1]: *** [install-recursive] Error 1
make: *** [install] Error 2



gcc output:

CC       libpulsecore_2.98_la-svolume_mmx.lo
{standard input}:67:bad register name `%rdx, %edi,4)'
{standard input}:95:bad register name `%rdx, %edi,4)'
{standard input}:121:bad register name `%rdx, %edi,4)'
{standard input}:122:bad register name `%rdx, %edi,4)'
{standard input}:201:bad register name `%rdx, %edi,4)'
{standard input}:231:bad register name `%rdx, %edi,4)'
{standard input}:265:bad register name `%rdx, %edi,4)'
{standard input}:266:bad register name `%rdx, %edi,4)'
lipo: can't open input file: /var/tmp//ccw2a05M.out (No such file or directory)
make[3]: *** [libpulsecore_2.98_la-svolume_mmx.lo] Error 1
make[2]: *** [install] Error 2
make[1]: *** [install-recursive] Error 1
make: *** [install] Error 2