Add a Makefile for building the cloudabi32 kernel module.

Where the cloudabi64 kernel can be used to execute 64-bit CloudABI
binaries, this one should be used for 32-bit binaries. Right now it
works on i386 and amd64.

sys/modules/Makefile

@@ -75,6 +75,7 @@ SUBDIR=	\
 	${_cfi} \
 	${_ciss} \
 	cloudabi \
+	${_cloudabi32} \
 	${_cloudabi64} \
 	${_cm} \
 	${_cmx} \
@@ -765,6 +766,9 @@ _epic=		epic
 _igb=		igb
 .endif
 
+.if ${MACHINE_CPUARCH} == "amd64" || ${MACHINE_CPUARCH} == "i386"
+_cloudabi32=	cloudabi32
+.endif
 .if ${MACHINE_CPUARCH} == "aarch64" || ${MACHINE_CPUARCH} == "amd64"
 _cloudabi64=	cloudabi64
 .endif

sys/modules/cloudabi32/Makefile

@@ -0,0 +1,37 @@
+# $FreeBSD$
+
+SYSDIR?=${.CURDIR}/../..
+
+.PATH: ${SYSDIR}/compat/cloudabi32
+.PATH: ${SYSDIR}/${MACHINE}/cloudabi32
+
+KMOD=	cloudabi32
+SRCS=	cloudabi32_fd.c cloudabi32_module.c cloudabi32_poll.c \
+	cloudabi32_sock.c cloudabi32_syscalls.c cloudabi32_sysent.c \
+	cloudabi32_sysvec.c cloudabi32_thread.c
+
+OBJS=	cloudabi32_vdso_blob.o
+CLEANFILES=cloudabi32_vdso.o
+
+.if ${MACHINE_CPUARCH} == "i386"
+VDSO_SRCS=${SYSDIR}/contrib/cloudabi/cloudabi_vdso_i686.S
+OUTPUT_TARGET=elf32-i386-freebsd
+BINARY_ARCHITECTURE=aarch32
+.elif ${MACHINE_CPUARCH} == "amd64"
+VDSO_SRCS=${SYSDIR}/contrib/cloudabi/cloudabi_vdso_i686_on_64bit.S
+OUTPUT_TARGET=elf64-x86-64-freebsd
+BINARY_ARCHITECTURE=i386
+.endif
+
+cloudabi32_vdso.o: ${VDSO_SRCS}
+	${CC} -x assembler-with-cpp -m32 -shared -nostdinc -nostdlib \
+	    -Wl,-T${SYSDIR}/compat/cloudabi/cloudabi_vdso.lds \
+	    ${VDSO_SRCS} -o ${.TARGET}
+
+cloudabi32_vdso_blob.o: cloudabi32_vdso.o
+	${OBJCOPY} --input-target binary \
+	    --output-target ${OUTPUT_TARGET} \
+	    --binary-architecture ${BINARY_ARCHITECTURE} \
+	    cloudabi32_vdso.o ${.TARGET}
+
+.include <bsd.kmod.mk>