Add option to suppress SIP warnings (#3230)

to fix travis builds for OSX. Yay

ci/travis/osx/install.sh

@@ -18,9 +18,17 @@ cd build
 #no PGTEST for OSX - can't get postgres to start with brew install
 #no APIDOC for OSX - doxygen tests and warnings are covered by linux build
 #no deprecated-declarations warnings... requires QGIS ported to Cocoa
-cmake -DWITH_SERVER=ON -DWITH_STAGED_PLUGINS=ON -DWITH_GRASS=OFF \
-          -DSUPPRESS_QT_WARNINGS=ON -DENABLE_MODELTEST=ON -DENABLE_PGTEST=OFF \
-          -DWITH_QWTPOLAR=OFF -DWITH_PYSPATIALITE=ON \
-          -DQWT_INCLUDE_DIR=/usr/local/opt/qwt/lib/qwt.framework/Headers/ \
-          -DQWT_LIBRARY=/usr/local/opt/qwt/lib/qwt.framework/qwt \
-          -DCMAKE_CXX_FLAGS="-Wno-deprecated-declarations" ..
+cmake \
+  -DWITH_SERVER=ON \
+  -DWITH_STAGED_PLUGINS=ON \
+  -DWITH_GRASS=OFF \
+  -DSUPPRESS_SIP_WARNINGS=ON \
+  -DSUPPRESS_QT_WARNINGS=ON \
+  -DENABLE_MODELTEST=ON \
+  -DENABLE_PGTEST=OFF \
+  -DWITH_QWTPOLAR=OFF \
+  -DWITH_PYSPATIALITE=ON \
+  -DQWT_INCLUDE_DIR=/usr/local/opt/qwt/lib/qwt.framework/Headers/ \
+  -DQWT_LIBRARY=/usr/local/opt/qwt/lib/qwt.framework/qwt \
+  -DCMAKE_CXX_FLAGS="-Wno-deprecated-declarations" \
+  ..

cmake/SIPMacros.cmake

@@ -93,6 +93,11 @@ MACRO(GENERATE_SIP_PYTHON_MODULE_CODE MODULE_NAME MODULE_SIP CPP_FILES)
   ENDIF(PEDANTIC)
 
   SET(SIPCMD ${SIP_BINARY_PATH} ${_sip_tags} -w -e ${_sip_x} ${SIP_EXTRA_OPTIONS} -j ${SIP_CONCAT_PARTS} -c ${CMAKE_CURRENT_BINARY_DIR}/${_module_path} ${_sip_includes} ${_abs_module_sip})
+  SET(SUPPRESS_SIP_WARNINGS FALSE CACHE BOOL "Hide SIP warnings")
+  MARK_AS_ADVANCED(SUPPRESS_SIP_WARNINGS)
+  IF(SUPPRESS_SIP_WARNINGS)
+    SET(SIPCMD ${SIPCMD} 2> /dev/null || true)
+  ENDIF(SUPPRESS_SIP_WARNINGS)
 
   ADD_CUSTOM_COMMAND(
     OUTPUT ${_sip_output_files}
@@ -100,6 +105,7 @@ MACRO(GENERATE_SIP_PYTHON_MODULE_CODE MODULE_NAME MODULE_SIP CPP_FILES)
     COMMAND ${CMAKE_COMMAND} -E touch ${_sip_output_files}
     COMMAND ${SIPCMD}
     DEPENDS ${_abs_module_sip} ${SIP_EXTRA_FILES_DEPEND}
+    VERBATIM
   )
 
   ADD_CUSTOM_TARGET(generate_sip_${MODULE_NAME}_cpp_files DEPENDS ${_sip_output_files})