add meson option to disable cplusplus api build

ChangeLog

@@ -27,6 +27,7 @@ master
 - EXIF support for PNG load and save
 - deprecate gifsave reoptimise, add reuse
 - add "encoder" to heifsave [dloebl]
+- add "cplusplus" meson build option [jcupitt]
 
 9/11/22 started 8.13.4
 - missing include in mosaic_fuzzer [ServOKio]

README.md

@@ -89,7 +89,7 @@ There are basic bash completions in `completions/`, see the README in there.
 
 ```
 cd libvips-x.y.x
-meson build --prefix /my/install/prefix
+meson setup build --prefix /my/install/prefix
 cd build
 meson compile
 meson test

meson.build

@@ -637,6 +637,7 @@ build_summary = {
      'enable doxygen': [get_option('doxygen')],
      'enable introspection': [get_option('introspection')],
      'enable examples': [get_option('examples')],
+     'enable cplusplus': [get_option('cplusplus')],
      'enable RAD load/save': [get_option('radiance')],
      'enable Analyze7 load/save': [get_option('analyze')],
      'enable PPM load/save': [get_option('ppm')],
@@ -689,7 +690,9 @@ endif
 if get_option('examples')
   subdir('examples')
 endif
+if get_option('cplusplus')
   subdir('cplusplus')
+endif
 
 # these lines removed by a regexp for oss-fuzz builds, don't touch!
 subdir('man')

meson_options.txt

@@ -10,6 +10,11 @@ option('examples',
   value: true, 
   description: 'Build example programs')
 
+option('cplusplus', 
+  type: 'boolean', 
+  value: true, 
+  description: 'Build C++ API')
+
 option('doxygen', 
   type: 'boolean', 
   value: false, 

test/test_threading.sh

@@ -48,7 +48,7 @@ fi
 
 # setting VIPS_MAX_THREADS low should force a small thread limit
 echo -n "checking threadset size limit ... "
-VIPS_MAX_THREADS=5 VIPS_CONCURRENCY=3 vips copy $image x.v || exit_code=$?
+VIPS_MAX_THREADS=5 VIPS_CONCURRENCY=3 $vips copy $image x.v || exit_code=$?
 if [ $exit_code -ne 0 ]; then
   echo FAILED
   exit 1