[PATCH 7/9] util: Use meson checks for valloc() and memalign() presence

[Peter Maydell <peter.maydell@linaro.org>]

Instead of assuming that all CONFIG_BSD have valloc() and anything
else is memalign(), explicitly check for those functions in
meson.build and use the "is the function present" define.  Tests for
specific functionality are better than which-OS checks; this also
lets us give a helpful error message if somehow there's no usable
function present.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 meson.build     | 2 ++
 util/memalign.c | 8 ++++++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/meson.build b/meson.build
index 21511d4fb61..1c44198ebda 100644
--- a/meson.build
+++ b/meson.build
@@ -1610,6 +1610,8 @@ config_host_data.set('CONFIG_POSIX_FALLOCATE', cc.has_function('posix_fallocate'
 # thinking that Windows has posix_memalign()
 config_host_data.set('CONFIG_POSIX_MEMALIGN', cc.has_function('posix_memalign', prefix: '#include <stdlib.h>'))
 config_host_data.set('CONFIG_ALIGNED_MALLOC', cc.has_function('_aligned_malloc'))
+config_host_data.set('CONFIG_VALLOC', cc.has_function('valloc'))
+config_host_data.set('CONFIG_MEMALIGN', cc.has_function('memalign'))
 config_host_data.set('CONFIG_PPOLL', cc.has_function('ppoll'))
 config_host_data.set('CONFIG_PREADV', cc.has_function('preadv', prefix: '#include <sys/uio.h>'))
 config_host_data.set('CONFIG_SEM_TIMEDWAIT', cc.has_function('sem_timedwait', dependencies: threads))
diff --git a/util/memalign.c b/util/memalign.c
index ee3393cc601..fc8228bffb5 100644
--- a/util/memalign.c
+++ b/util/memalign.c
@@ -25,6 +25,8 @@
  */
 
 #include "qemu/osdep.h"
+#include "qemu/host-utils.h"
+#include "trace.h"
 
 void *qemu_try_memalign(size_t alignment, size_t size)
 {
@@ -50,10 +52,12 @@ void *qemu_try_memalign(size_t alignment, size_t size)
     } else {
         ptr = NULL;
     }
-#elif defined(CONFIG_BSD)
+#elif defined(CONFIG_VALLOC)
     ptr = valloc(size);
-#else
+#elif defined(CONFIG_MEMALIGN)
     ptr = memalign(alignment, size);
+#else
+    #error No function to allocate aligned memory available
 #endif
     trace_qemu_memalign(alignment, size, ptr);
     return ptr;
-- 
2.25.1