build: Use the appropriate linker flags

We need to check if the linker flags we use are available, depending on
the platform, and we need to ensure that the shared library is
versioned appropriately.

gtk/meson.build

@@ -876,12 +876,13 @@ endforeach
 # Library
 
 libgtk = shared_library('gtk-4',
+  soversion: gtk_soversion,
   sources: [typefuncs, gtk_sources, gtkmarshal_h, gtkprivatetypebuiltins_h],
   c_args: gtk_cargs + common_cflags,
   include_directories: [confinc, gdkinc, gtkinc],
   dependencies: gtk_deps + [libgdk_dep, libgsk_dep],
   link_with: [libgdk, libgsk, included_input_modules],
-  link_args: ['-Bsymbolic'],
+  link_args: common_ldflags,
   install: true)
 
 libgtk_dep = declare_dependency(
@@ -889,7 +890,7 @@ libgtk_dep = declare_dependency(
   include_directories: [confinc, gtkinc],
   dependencies: gtk_deps + [libgdk_dep, libgsk_dep],
   link_with: libgtk,
-  link_args: ['-Bsymbolic'])
+  link_args: common_ldflags)
 
 # Installed tools
 

meson.build

@@ -68,6 +68,8 @@ gtk_binary_version = '4.0.0'
 
 gtk_binary_age = 100 * gtk_minor_version + gtk_micro_version
 
+gtk_soversion = '0.@0@.@1@'.format(gtk_binary_age - gtk_interface_age, gtk_interface_age)
+
 gtk_api_version = '4.0'
 
 x11_enabled      = get_option('enable-x11-backend')
@@ -272,6 +274,21 @@ if get_option('default_library') != 'static'
   endif
 endif
 
+common_ldflags = []
+
+if host_machine.system() == 'linux'
+  foreach ldflag: [ '-Wl,-Bsymbolic', '-Wl,-z,relro', '-Wl,-z,now', ]
+    if cc.has_argument(ldflag)
+      common_ldflags += [ ldflag ]
+    endif
+  endforeach
+endif
+
+# Maintain compatibility with autotools
+if host_machine.system() == 'darwin'
+  common_ldflags += [ '-compatibility_version=1', '-current_version=1.0', ]
+endif
+
 confinc = include_directories('.')
 gdkinc = include_directories('gdk')
 gtkinc = include_directories('gtk')