[gvfs] build: Fix statfs check on FreeBSD

[Ondrej Holy <oholy src gnome org>]

commit 623ccee4bd9779ca8d86787d2c2f90667fe6fce6
Author: Ting-Wei Lan <lantw src gnome org>
Date:   Sun Dec 24 21:37:59 2017 +0800

    build: Fix statfs check on FreeBSD
    
    To include a header without the possibility of causing 'no such file or
    directory' error, we have to check for it before including it.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=786149

 meson.build |   40 ++++++++++++++++++++++------------------
 1 files changed, 22 insertions(+), 18 deletions(-)
---
diff --git a/meson.build b/meson.build
index 085a6a0..7d1cebd 100644
--- a/meson.build
+++ b/meson.build
@@ -89,10 +89,29 @@ config_h.set('HAVE_OPENPTY', have_openpty,
 config_h.set('HAVE_LOGIN_TTY', util_dep.found() and cc.has_function('login_tty', dependencies: util_dep),
              description: 'Whether login_tty is available')
 
+# headers
+check_headers = [
+  # fs + pty
+  ['HAVE_SYS_PARAM_H', 'sys/param.h'],
+  # fs
+  ['HAVE_SYS_MOUNT_H', 'sys/mount.h'],
+  ['HAVE_SYS_STATFS_H', 'sys/statfs.h'],
+  ['HAVE_SYS_STATVFS_H', 'sys/statvfs.h'],
+  ['HAVE_SYS_VFS_H', 'sys/vfs.h']
+]
+
+statfs_includes = ''
+
+foreach header: check_headers
+  has_header = cc.has_header(header[1])
+  config_h.set10(header[0], has_header)
+  if has_header
+    statfs_includes += '#include <@0@>\n'.format(header[1])
+  endif
+endforeach
+
 # if statfs() takes 2 arguments (Posix) or 4 (Solaris)
-statfs_code = '''
-  #include <sys/statfs.h>
-  #include <sys/vfs.h>
+statfs_code = statfs_includes + '''
   int main() {
     struct statfs st;
     @0@;
@@ -107,21 +126,6 @@ else
   error('unable to determine number of arguments to statfs()')
 endif
 
-# headers
-check_headers = [
-  # fs + pty
-  ['HAVE_SYS_PARAM_H', 'sys/param.h'],
-  # fs
-  ['HAVE_SYS_MOUNT_H', 'sys/mount.h'],
-  ['HAVE_SYS_STATFS_H', 'sys/statfs.h'],
-  ['HAVE_SYS_STATVFS_H', 'sys/statvfs.h'],
-  ['HAVE_SYS_VFS_H', 'sys/vfs.h']
-]
-
-foreach header: check_headers
-  config_h.set10(header[0], cc.has_header(header[1]))
-endforeach
-
 # pty
 check_headers = [
   ['HAVE_STROPTS_H', 'stropts.h'],