[PATCH v9 05/11] osdep: build with non-working system() function

[Joelle van Dyne <j@getutm.app>]

Build without error on hosts without a working system(). If system()
is called, return -1 with ENOSYS.

Signed-off-by: Joelle van Dyne <j@getutm.app>
---
 meson.build          |  1 +
 include/qemu/osdep.h | 12 ++++++++++++
 2 files changed, 13 insertions(+)

diff --git a/meson.build b/meson.build
index f1e67b8cd1..a7650956d3 100644
--- a/meson.build
+++ b/meson.build
@@ -1118,6 +1118,7 @@ config_host_data.set('HAVE_SYS_IOCCOM_H', cc.has_header('sys/ioccom.h'))
 config_host_data.set('HAVE_SYS_KCOV_H', cc.has_header('sys/kcov.h'))
 config_host_data.set('HAVE_HOST_BLOCK_DEVICE', have_host_block_device)
 config_host_data.set('HAVE_SYS_DISK_H', cc.has_header('sys/disk.h'))
+config_host_data.set('HAVE_SYSTEM_FUNCTION', cc.has_function('system', prefix: '#include <stdlib.h>'))
 
 ignored = ['CONFIG_QEMU_INTERP_PREFIX'] # actually per-target
 arrays = ['CONFIG_AUDIO_DRIVERS', 'CONFIG_BDRV_RW_WHITELIST', 'CONFIG_BDRV_RO_WHITELIST']
diff --git a/include/qemu/osdep.h b/include/qemu/osdep.h
index a434382c58..5bd1a67769 100644
--- a/include/qemu/osdep.h
+++ b/include/qemu/osdep.h
@@ -682,4 +682,16 @@ char *qemu_get_host_name(Error **errp);
  */
 size_t qemu_get_host_physmem(void);
 
+/**
+ * Platforms which do not support system() return ENOSYS
+ */
+#ifndef HAVE_SYSTEM_FUNCTION
+#define system platform_does_not_support_system
+static inline int platform_does_not_support_system(const char *command)
+{
+    errno = ENOSYS;
+    return -1;
+}
+#endif /* !HAVE_SYSTEM_FUNCTION */
+
 #endif
-- 
2.28.0