+# kvm probe
+if test "$kvm" = "yes" ; then
+ cat > $TMPC <<EOF
+#include <linux/kvm.h>
+#if !defined(KVM_API_VERSION) || KVM_API_VERSION < 12 || KVM_API_VERSION > 12
+#error Invalid KVM version
+#endif
+#if !defined(KVM_CAP_USER_MEMORY)
+#error Missing KVM capability KVM_CAP_USER_MEMORY
+#endif
+#if !defined(KVM_CAP_SET_TSS_ADDR)
+#error Missing KVM capability KVM_CAP_SET_TSS_ADDR
+#endif
+#if !defined(KVM_CAP_DESTROY_MEMORY_REGION_WORKS)
+#error Missing KVM capability KVM_CAP_DESTROY_MEMORY_REGION_WORKS
+#endif
+int main(void) { return 0; }
+EOF
+ if test "$kerneldir" != "" ; then
+ kvm_cflags=-I"$kerneldir"/include
+ if test \( "$cpu" = "i386" -o "$cpu" = "x86_64" \) \
+ -a -d "$kerneldir/arch/x86/include" ; then
+ kvm_cflags="$kvm_cflags -I$kerneldir/arch/x86/include"
+ elif test "$cpu" = "ppc" -a -d "$kerneldir/arch/powerpc/include" ; then
+ kvm_cflags="$kvm_cflags -I$kerneldir/arch/powerpc/include"
+ elif test -d "$kerneldir/arch/$cpu/include" ; then
+ kvm_cflags="$kvm_cflags -I$kerneldir/arch/$cpu/include"
+ fi
+ else
+ kvm_cflags=""
+ fi
+ if $cc $ARCH_CFLAGS -o $TMPE ${OS_CFLAGS} $kvm_cflags $TMPC \
+ > /dev/null 2>/dev/null ; then
+ :
+ else
+ kvm="no";
+ if [ -x "`which awk 2>/dev/null`" ] && \
+ [ -x "`which grep 2>/dev/null`" ]; then
+ kvmerr=`LANG=C $cc $ARCH_CFLAGS -o $TMPE ${OS_CFLAGS} $kvm_cflags $TMPC 2>&1 \
+ | grep "error: " \
+ | awk -F "error: " '{if (NR>1) printf(", "); printf("%s",$2);}'`
+ if test "$kvmerr" != "" ; then
+ kvm="no - (${kvmerr})"
+ fi
+ fi
+ fi
+fi
+
+##########################################
+# pthread probe
+PTHREADLIBS=""
+
+if test "$pthread" = yes; then
+ pthread=no
+cat > $TMPC << EOF
+#include <pthread.h>
+int main(void) { pthread_mutex_t lock; return 0; }
+EOF
+ if $cc $ARCH_CFLAGS -o $TMPE $PTHREADLIBS $TMPC 2> /dev/null > /dev/null ; then
+ pthread=yes
+ PTHREADLIBS="-lpthread"
+ fi
+fi
+
+if test "$pthread" = no; then
+ aio=no
+ io_thread=no
+fi
+
+##########################################
+# iovec probe
+cat > $TMPC <<EOF
+#include <sys/types.h>
+#include <sys/uio.h>
+#include <unistd.h>
+int main(void) { struct iovec iov; return 0; }
+EOF
+iovec=no
+if $cc $ARCH_CFLAGS -o $TMPE $TMPC > /dev/null 2> /dev/null ; then
+ iovec=yes
+fi
+
+##########################################
+# preadv probe
+cat > $TMPC <<EOF
+#include <sys/types.h>
+#include <sys/uio.h>
+#include <unistd.h>
+int main(void) { preadv; }
+EOF
+preadv=no
+if $cc $ARCH_CFLAGS -o $TMPE $TMPC > /dev/null 2> /dev/null ; then
+ preadv=yes
+fi
+
+##########################################
+# fdt probe
+if test "$fdt" = "yes" ; then
+ fdt=no
+ cat > $TMPC << EOF
+int main(void) { return 0; }
+EOF
+ if $cc $ARCH_CFLAGS -o $TMPE ${OS_CFLAGS} $TMPC -lfdt 2> /dev/null > /dev/null ; then
+ fdt=yes
+ fi
+fi
+
+#
+# Check for xxxat() functions when we are building linux-user
+# emulator. This is done because older glibc versions don't
+# have syscall stubs for these implemented.
+#
+atfile=no
+if [ "$linux_user" = "yes" ] ; then