[glib/nirbheek/gmodule-symbol-uscore: 1/3] gmodule: Use meson compiler method for symbol underscore checks

[Nirbheek Chauhan <nirbheekc src gnome org>]

commit acace2dd31897286eb6c9ac940559eb9114c1ef5
Author: Nirbheek Chauhan <nirbheek centricular com>
Date:   Sat Jul 13 11:08:37 2019 +0530

    gmodule: Use meson compiler method for symbol underscore checks
    
    This is much simpler and also works when cross-compiling.

 gmodule/meson.build | 47 ++++++++---------------------------------------
 1 file changed, 8 insertions(+), 39 deletions(-)
---
diff --git a/gmodule/meson.build b/gmodule/meson.build
index a7a2a5c87..be9e4cb9f 100644
--- a/gmodule/meson.build
+++ b/gmodule/meson.build
@@ -8,18 +8,8 @@ libdl_dep = [ ]
 g_module_lib_args = [ ]
 g_module_impl = ''
 
-dlopen_dlsym_test_code = '''
-#include <dlfcn.h>
-int glib_underscore_test (void) { return 42; }
-int main (int argc, char ** argv) {
-  void *f1 = (void*)0, *f2 = (void*)0, *handle;
-  handle = dlopen ((void*)0, 0);
-  if (handle) {
-    f1 = dlsym (handle, "glib_underscore_test");
-    f2 = dlsym (handle, "_glib_underscore_test");
-  }
-  return (!f2 || f1);
-}'''
+# Check whether we need preceding underscores
+g_module_need_uscore = cc.symbols_have_underscore_prefix()
 
 # On Windows force native WIN32 shared lib loader
 if host_system == 'windows'
@@ -28,42 +18,21 @@ if host_system == 'windows'
 # dlopen() filepath must be of the form /path/libname.a(libname.so)
 elif host_system == 'aix'
   g_module_impl = 'G_MODULE_IMPL_AR'
-elif cc.links(dlopen_dlsym_test_code, name : 'dlopen() and dlsym() in system libraries')
+elif cc.has_function('dlopen', prefix : '#include <dlfcn.h>')
   g_module_impl = 'G_MODULE_IMPL_DL'
 # NSLinkModule (dyld) in system libraries (Darwin)
 elif cc.has_function('NSLinkModule')
   g_module_impl = 'G_MODULE_IMPL_DYLD'
-  g_module_need_uscore = 1
-elif cc.links(dlopen_dlsym_test_code, args : '-ldl', name : 'dlopen() and dlsym() in libdl')
+elif cc.has_function('dlopen', prefix : '#include <dlfcn.h>', args : '-ldl')
   g_module_impl = 'G_MODULE_IMPL_DL'
   libdl_dep = cc.find_library('dl')
   g_module_lib_args = '-ldl'
 endif
 
 # additional checks for G_MODULE_IMPL_DL
-if g_module_impl == 'G_MODULE_IMPL_DL'
-  # FIXME: check for OSF1/5.0 RTLD_GLOBAL brokenness (is this still relevant?)
-
-  # Check whether we need preceding underscores
-  if cc.get_id() == 'msvc'
-    message('Building for MSVC: assuming that symbols are prefixed with underscore')
-    g_module_need_uscore = 1
-  elif meson.has_exe_wrapper()
-    # FIXME: communicate result via stdout instead of return value, so non-0 return is not printed in bold 
red
-    rres = cc.run(dlopen_dlsym_test_code,
-                  args : g_module_lib_args,
-                  name : 'dlsym() preceding underscores')
-    if host_system == 'windows' or rres.returncode() == 0
-      g_module_need_uscore = 1
-    endif
-  else
-    message('Cross-compiling: assuming that symbols aren\'t prefixed with underscore')
-    g_module_need_uscore = 0
-  endif
-
-  if cc.has_function('dlerror', args : g_module_lib_args)
-    g_module_have_dlerror = 1
-  endif
+# FIXME: check for OSF1/5.0 RTLD_GLOBAL brokenness (is this still relevant?)
+if g_module_impl == 'G_MODULE_IMPL_DL' and cc.has_function('dlerror', args : g_module_lib_args)
+  g_module_have_dlerror = 1
 endif
 
 # Done, have we got an implementation?
@@ -75,7 +44,7 @@ endif
 gmoduleconf_conf.set('G_MODULE_IMPL', g_module_impl)
 gmoduleconf_conf.set('G_MODULE_SUPPORTED', g_module_impl != '0')
 gmoduleconf_conf.set('G_MODULE_HAVE_DLERROR', g_module_have_dlerror)
-gmoduleconf_conf.set('G_MODULE_NEED_USCORE', g_module_need_uscore)
+gmoduleconf_conf.set10('G_MODULE_NEED_USCORE', g_module_need_uscore)
 gmoduleconf_conf.set('G_MODULE_BROKEN_RTLD_GLOBAL', g_module_broken_rtld_global)
 
 gmoduleconf_h = configure_file(input : 'gmoduleconf.h.in',