meson: Rely only on extracted version in lz4.h

So now instead of warning when failing to extract version number
from lz4.h, we error and stop the build instead.

.travis.yml

@@ -178,9 +178,9 @@ matrix:
       compiler: clang
       install:
         - sudo apt-get install -qq python3 tree
-        - curl -o ~/ninja.zip -L 'https://github.com/ninja-build/ninja/releases/download/v1.9.0/ninja-linux.zip'
+        - travis_retry curl -o ~/ninja.zip -L 'https://github.com/ninja-build/ninja/releases/download/v1.9.0/ninja-linux.zip'
             && unzip ~/ninja.zip -d ~/.local/bin
-        - curl -o ~/get-pip.py 'https://bootstrap.pypa.io/get-pip.py'
+        - travis_retry curl -o ~/get-pip.py 'https://bootstrap.pypa.io/get-pip.py'
             && python3 ~/get-pip.py --user
             && pip3 install --user meson
       script:

contrib/meson/meson.build

@@ -11,9 +11,7 @@ project('lz4', ['c'],
   license: ['BSD', 'GPLv2'],
   default_options : ['c_std=c99',
     'buildtype=release'],
-  # Fall-back version in case of extracting version number from
+  version: 'DUMMY',
-  # `lz4.h` failed.
-  version: '1.9.1',
   meson_version: '>=0.47.0')
 
 cc = meson.get_compiler('c')
@@ -40,13 +38,10 @@ lz4_h_file = join_paths(meson.current_source_dir(), '../../lib/lz4.h')
 GetLz4LibraryVersion_py = files('GetLz4LibraryVersion.py')
 r = run_command(python3, GetLz4LibraryVersion_py, lz4_h_file)
 if r.returncode() == 0
-  output = r.stdout().strip()
+  lz4_version = r.stdout().strip()
-  if output.version_compare('>@0@'.format(lz4_version))
+  message('Project version is now: @0@'.format(lz4_version))
-    lz4_version = output
-    message('Project version is now: @0@'.format(lz4_version))
-  endif
 else
-  warning('Cannot find project version in @0@'.format(lz4_h_file))
+  error('Cannot find project version in @0@'.format(lz4_h_file))
 endif
 
 lz4_libversion = lz4_version