HACK: android: Make libjpeg optional

* To build using NDK.

src/android/camera_stream.cpp

@@ -15,7 +15,9 @@
 
 #include <libcamera/formats.h>
 
+#ifdef HAVE_LIBJPEG
 #include "jpeg/post_processor_jpeg.h"
+#endif
 #include "yuv/post_processor_yuv.h"
 
 #include "camera_buffer.h"
@@ -97,9 +99,11 @@ int CameraStream::configure()
 			postProcessor_ = std::make_unique<PostProcessorYuv>();
 			break;
 
+#ifdef HAVE_LIBJPEG
 		case formats::MJPEG:
 			postProcessor_ = std::make_unique<PostProcessorJpeg>(cameraDevice_);
 			break;
+#endif
 
 		default:
 			LOG(HAL, Error) << "Unsupported format: " << outFormat;

src/android/meson.build

@@ -1,8 +1,6 @@
 # SPDX-License-Identifier: CC0-1.0
 
 android_deps = [
-    dependency('libexif', required : get_option('android')),
-    dependency('libjpeg', required : get_option('android')),
     libcamera_private,
     libyuv_dep,
 ]
@@ -16,6 +14,12 @@ foreach dep : android_deps
     endif
 endforeach
 
+libjpeg_dep = dependency('libjpeg', required : false)
+if libjpeg_dep.found()
+    config_h.set('HAVE_LIBJPEG', 1)
+    dependency('libexif', required : true)
+endif
+
 android_hal_sources = files([
     'camera3_hal.cpp',
     'camera_capabilities.cpp',
@@ -33,7 +37,9 @@ android_hal_sources = files([
 android_cpp_args = []
 
 subdir('cros')
-subdir('jpeg')
+if libjpeg_dep.found()
+    subdir('jpeg')
+endif
 subdir('mm')
 
 android_camera_metadata_sources = files([

src/libcamera/pipeline/virtual/meson.build

@@ -7,9 +7,11 @@ libcamera_internal_sources += files([
     'virtual.cpp',
 ])
 
-libjpeg = dependency('libjpeg', required : true)
+libjpeg = dependency('libjpeg', required : false)
 
 libcamera_deps += [libyuv_dep]
-libcamera_deps += [libjpeg]
+if libjpeg.found()
+  libcamera_deps += [libjpeg]
+endif
 
 subdir('data')

src/meson.build

@@ -53,7 +53,10 @@ if (pipelines.contains('virtual') or get_option('android').allowed()) and \
          '-Wno-sign-compare',
          '-Wno-unused-variable',
          '-Wno-unused-parameter')
-    libyuv_vars.append_link_args('-ljpeg')
+    libjpeg = dependency('libjpeg', required : false)
+    if libjpeg.found()
+      libyuv_vars.append_link_args('-ljpeg')
+    endif
     libyuv = cmake.subproject('libyuv', options : libyuv_vars)
 
     # Meson fails to apply the -fPIC flag to static libraries produced by CMake