examples: stop processing meson file if build impossible

Once it has been determined that an example cannot be built, there is
little point in continuing to process the meson.build file for that
example, so we can use subdir_done() to return to the calling file.
This can potentially prevent problems where later statement in the file
may cause an error on systems where the app cannot be built, e.g. on
Windows or FreeBSD.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>

examples/distributor/meson.build

@@ -8,6 +8,9 @@
 
 # require the power library
 build = dpdk_conf.has('RTE_LIB_POWER')
+if not build
+	subdir_done()
+endif
 
 allow_experimental_apis = true
 deps += ['distributor', 'power']

examples/ethtool/meson.build

@@ -7,6 +7,10 @@
 # DPDK instance, use 'make'
 
 build = is_linux
+if not build
+	subdir_done()
+endif
+
 sources = files('lib/rte_ethtool.c',
 	'ethtool-app/ethapp.c',
 	'ethtool-app/main.c')

examples/ioat/meson.build

@@ -8,6 +8,9 @@
 
 allow_experimental_apis = true
 build = dpdk_conf.has('RTE_RAW_IOAT')
+if not build
+	subdir_done()
+endif
 
 deps += ['raw_ioat']
 

examples/ip_pipeline/meson.build

@@ -7,6 +7,10 @@
 # DPDK instance, use 'make'
 
 build = cc.has_header('sys/epoll.h')
+if not build
+	subdir_done()
+endif
+
 deps += ['pipeline', 'bus_pci']
 allow_experimental_apis = true
 sources = files(

examples/kni/meson.build

@@ -8,6 +8,10 @@
 
 # this app can be built if-and-only-if KNI library is buildable
 build = dpdk_conf.has('RTE_LIB_KNI')
+if not build
+	subdir_done()
+endif
+
 deps += ['kni', 'bus_pci']
 sources = files(
 	'main.c'

examples/l2fwd-cat/meson.build

@@ -8,6 +8,10 @@
 
 pqos = cc.find_library('pqos', required: false)
 build = pqos.found()
+if not build
+	subdir_done()
+endif
+
 ext_deps += pqos
 allow_experimental_apis = true
 cflags += '-I/usr/local/include' # assume pqos lib installed in /usr/local

examples/ntb/meson.build

@@ -9,7 +9,9 @@
 allow_experimental_apis = true
 if not is_linux
 	build = false
+	subdir_done()
 endif
+
 deps += 'rawdev'
 cflags += ['-D_FILE_OFFSET_BITS=64']
 sources = files(

examples/performance-thread/l3fwd-thread/meson.build

@@ -7,6 +7,10 @@
 # DPDK instance, use 'make'
 
 build = dpdk_conf.has('RTE_ARCH_X86_64')
+if not build
+	subdir_done()
+endif
+
 deps += ['timer', 'lpm']
 allow_experimental_apis = true
 

examples/performance-thread/pthread_shim/meson.build

@@ -7,6 +7,10 @@
 # DPDK instance, use 'make'
 
 build = dpdk_conf.has('RTE_ARCH_X86_64') or dpdk_conf.has('RTE_ARCH_ARM64')
+if not build
+	subdir_done()
+endif
+
 deps += ['timer']
 allow_experimental_apis = true
 

examples/pipeline/meson.build

@@ -7,6 +7,10 @@
 # DPDK instance, use 'make'
 
 build = cc.has_header('sys/epoll.h')
+if not build
+	subdir_done()
+endif
+
 deps += ['pipeline', 'bus_pci']
 allow_experimental_apis = true
 sources = files(

examples/vdpa/meson.build

@@ -8,7 +8,9 @@
 
 if not is_linux
 	build = false
+	subdir_done()
 endif
+
 deps += 'vhost'
 allow_experimental_apis = true
 sources = files(

examples/vhost/meson.build

@@ -8,7 +8,9 @@
 
 if not is_linux
 	build = false
+	subdir_done()
 endif
+
 deps += 'vhost'
 allow_experimental_apis = true
 sources = files(

examples/vhost_blk/meson.build

@@ -8,10 +8,12 @@
 
 if not is_linux
 	build = false
+	subdir_done()
 endif
 
 if not cc.has_header('linux/virtio_blk.h')
 	build = false
+	subdir_done()
 endif
 
 deps += 'vhost'

examples/vhost_crypto/meson.build

@@ -7,6 +7,10 @@
 # DPDK instance, use 'make'
 
 build = dpdk_conf.has('RTE_LIB_VHOST')
+if not build
+	subdir_done()
+endif
+
 allow_experimental_apis = true
 deps += ['vhost', 'cryptodev']
 sources = files(