Adding IPO support.

CMakeLists.txt

@@ -1,8 +1,10 @@
-cmake_minimum_required(VERSION 3.1)
+cmake_minimum_required(VERSION 3.18)
 project(qwt VERSION 6.1.3 LANGUAGES CXX)
 
 option(WITH_EXAMPLES "Whether to include examples" OFF)
 
+include(CheckIPOSupported)
+
 add_subdirectory(src)
 add_subdirectory(textengines)
 

src/CMakeLists.txt

@@ -221,6 +221,8 @@ set(qwt_sources
 #----------------------------------------------------------------
 # Target
 #----------------------------------------------------------------
+check_ipo_supported(RESULT result OUTPUT output)
+
 if(QWT_USE_STATIC_LIBS)
     add_library(qwt STATIC ${qwt_headers} ${qwt_sources})
 else()
@@ -234,6 +236,13 @@ else()
     )
 endif()
 
+check_ipo_supported(RESULT result OUTPUT output)
+if(result)
+    set_target_properties(qwt PROPERTIES INTERPROCEDURAL_OPTIMIZATION_RELEASE ON)
+else()
+    message(WARNING "IPO is not supported: ${output}")
+endif()
+
 target_include_directories(qwt
 	PUBLIC
 		${PROJECT_SOURCE_DIR}/include

textengines/CMakeLists.txt

@@ -20,6 +20,12 @@ set(qwt_mathml_sources
 # Target
 #----------------------------------------------------------------
 add_library(qwt_mathml SHARED ${qwt_mathml_headers} ${qwt_mathml_sources})
+check_ipo_supported(RESULT result OUTPUT output)
+if(result)
+    set_target_properties(qwt_mathml PROPERTIES INTERPROCEDURAL_OPTIMIZATION_RELEASE ON)
+else()
+    message(WARNING "IPO is not supported: ${output}")
+endif()
 
 target_include_directories(qwt_mathml
 	PUBLIC