I'm building PortAudio 19 (today's snapshot) on Mac OS X 10.6 (Snow Leopard) and get the following error:
gcc -c -I./include -I./src/common -I./src/os/unix -std=c99 -g -O2 -DPA_LITTLE_ENDIAN -w -DPACKAGE_NAME=\"\" -DPACKAGE_TARNAME=\"\" -DPACKAGE_VERSION=\"\" -DPACKAGE_STRING=\"\" -DPACKAGE_BUGREPORT=\"\" -DSTDC_HEADERS=1 -DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1 -DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1 -DHAVE_UNISTD_H=1 -DHAVE_DLFCN_H=1 -DSIZEOF_SHORT=2 -DSIZEOF_INT=4 -DSIZEOF_LONG=8 -DHAVE_NANOSLEEP=1 -DPA_USE_COREAUDIO=1 src/hostapi/coreaudio/pa_mac_core.c -fno-common -DPIC -o src/hostapi/coreaudio/.libs/pa_mac_core.o
src/hostapi/coreaudio/pa_mac_core.c: In function 'OpenAndSetupOneAudioUnit':
src/hostapi/coreaudio/pa_mac_core.c:800: error: 'ComponentDescription' undeclared (first use in this function)
src/hostapi/coreaudio/pa_mac_core.c:800: error: (Each undeclared identifier is reported only once
src/hostapi/coreaudio/pa_mac_core.c:800: error: for each function it appears in.)
src/hostapi/coreaudio/pa_mac_core.c:800: error: expected ';' before 'desc'
src/hostapi/coreaudio/pa_mac_core.c:801: error: 'Component' undeclared (first use in this function)
src/hostapi/coreaudio/pa_mac_core.c:801: error: expected ';' before 'comp'
src/hostapi/coreaudio/pa_mac_core.c:866: error: 'desc' undeclared (first use in this function)
src/hostapi/coreaudio/pa_mac_core.c:872: error: 'comp' undeclared (first use in this function)
src/hostapi/coreaudio/pa_mac_core.c: At top level:
src/hostapi/coreaudio/pa_mac_core.c:2230: error: expected '=', ',', ';', 'asm' or '__attribute__' before 'BlockWhileAudioUnitIsRunning'
make: *** [src/hostapi/coreaudio/pa_mac_core.lo] Error 1