[gdk-pixbuf] build: Fix libjasper detection and usage on Meson/MSVC

[Chun-wei Fan <fanchunwei src gnome org>]

commit 859581953212b1b6950418f26e200a4bfa316432
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Wed Aug 23 14:40:24 2017 +0800

    build: Fix libjasper detection and usage on Meson/MSVC
    
    In order for MSVC builds that utilize libjasper to work, we need to
    ensure that JAS_WIN_MSVC_BUILD is defined when we check for
    jasper/jasper.h, and that same macro is defined when we compile
    io-jasper.c on MSVC.
    
    We also need to look for libjasper.lib on MSVC in case that jasper.lib
    cannot be found, as the Visual Studio projects for libjasper produces
    libjasper.lib upon build.
    
    https://bugzilla.gnome.org/show_bug?id=785767

 gdk-pixbuf/meson.build |    8 +++++---
 meson.build            |   22 +++++++++++++++++++++-
 2 files changed, 26 insertions(+), 4 deletions(-)
---
diff --git a/gdk-pixbuf/meson.build b/gdk-pixbuf/meson.build
index 0e8c8b4..866365c 100644
--- a/gdk-pixbuf/meson.build
+++ b/gdk-pixbuf/meson.build
@@ -17,7 +17,7 @@ loaders = [
   [ 'xbm', [ 'io-xbm.c' ] ],
   [ 'tga', [ 'io-tga.c', 'gdk-pixbuf-buffer-queue.c' ] ],
   [ 'icns', [ 'io-icns.c' ] ],
-  [ 'jasper', [ 'io-jasper.c' ], enabled_loaders.contains('jasper') ],
+  [ 'jasper', [ 'io-jasper.c' ], enabled_loaders.contains('jasper'), jasper_extra_cflags ],
   [ 'qtif', [ 'io-qtif.c' ] ]
 ]
 
@@ -109,6 +109,7 @@ foreach l: loaders
   name = l[0]
   sources = l[1]
   cond = l.get(2, true)
+  cflags = l.get(3, [])
 
   if cond and (builtin_loaders.contains(name) or builtin_all_loaders)
     cflag_for_included_loader = ['-DINCLUDE_@0@'.format(name)]
@@ -118,7 +119,7 @@ foreach l: loaders
                          sources,
                          dependencies: loaders_deps + gdk_pixbuf_deps,
                          include_directories: [ root_inc, gdk_pixbuf_inc ],
-                         c_args: common_cflags + gdk_pixbuf_cflags + cflag_for_included_loader)
+                         c_args: common_cflags + gdk_pixbuf_cflags + cflags + cflag_for_included_loader)
 
     included_loaders_deps += declare_dependency(link_with: mod)
   endif
@@ -148,13 +149,14 @@ foreach l: loaders
   name = l[0]
   sources = l[1]
   cond = l.get(2, true)
+  cflags = l.get(3, [])
 
   if cond and not (builtin_loaders.contains(name) or builtin_all_loaders)
     mod = shared_module('pixbufloader-@0@'.format(name),
                         sources,
                         dependencies: loaders_deps + gdk_pixbuf_deps + [ gdkpixbuf_dep ],
                         include_directories: [ root_inc, gdk_pixbuf_inc ],
-                        c_args: common_cflags + gdk_pixbuf_cflags,
+                        c_args: common_cflags + gdk_pixbuf_cflags + cflags,
                         install: true,
                         install_dir: gdk_pixbuf_loaderdir)
 
diff --git a/meson.build b/meson.build
index dd42b76..c8f1638 100644
--- a/meson.build
+++ b/meson.build
@@ -253,9 +253,29 @@ if get_option('enable_jpeg')
   endif
 endif
 
+jasper_extra_cflags = []
+
 if get_option('enable_jasper')
-  if cc.has_header('jasper/jasper.h')
+  has_jasper_header = false
+
+  if cc.get_id() == 'msvc'
+    # We must define JAS_WIN_MSVC_BUILD before including jasper/jasper.h on MSVC
+    jasper_msvc_macro = 'JAS_WIN_MSVC_BUILD'
+    has_jasper_header = cc.has_header('jasper/jasper.h', prefix: '#define @0@'.format(jasper_msvc_macro))
+    jasper_extra_cflags = [ '-D@0@'.format(jasper_msvc_macro) ]
+  else
+    has_jasper_header = cc.has_header('jasper/jasper.h')
+  endif
+
+  if has_jasper_header
     jasper_dep = cc.find_library('jasper', required: false)
+    if not jasper_dep.found()
+      if cc.get_id() == 'msvc'
+        # on MSVC, we need to look for libjasper.lib if jasper.lib is not found,
+        # which corresponds to what libjasper's MSVC projects produce
+        jasper_dep = cc.find_library('libjasper', required: false)
+      endif
+    endif
     if jasper_dep.found() and cc.has_function('jas_init', dependencies: jasper_dep)
       enabled_loaders += 'jasper'
       loaders_deps += jasper_dep