Update src/sage/meson.build

Co-authored-by: Tobias Diez <code@tobiasdiez.com>

Author: dimpase

src/sage/meson.build

@@ -31,7 +31,7 @@ conf_data.set('SAGE_ARCHFLAGS', 'unset')
 conf_data.set('SAGE_PKG_CONFIG_PATH', '')
 openmp = dependency('openmp', required: false, disabler: true)
 if openmp.found()
-  if host_machine.system() == 'darwin'
+if host_machine.system() == 'darwin'
     conf_data.set('OPENMP_CFLAGS', '-Xpreprocessor -fopenmp')
     conf_data.set('OPENMP_CXXFLAGS', '-Xpreprocessor -fopenmp')
 else