cmake: Raise the minimum required version to 3.6 and use its features
Use the `CMAKE_HOST_SOLARIS` variable, introduced in CMake 3.6, and
raise `cmake_minimum_required` accordingly.
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3da591e..b592132 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -33,7 +33,7 @@
# For conditions of distribution and use, see the disclaimer
# and license in png.h
-cmake_minimum_required(VERSION 3.5)
+cmake_minimum_required(VERSION 3.6)
set(PNGLIB_MAJOR 1)
set(PNGLIB_MINOR 6)
@@ -257,7 +257,7 @@
VERS_2 { global: sym2; main; } VERS_1;
")
set(_SAVED_CMAKE_REQUIRED_FLAGS ${CMAKE_REQUIRED_FLAGS})
- if(NOT CMAKE_HOST_SYSTEM_NAME MATCHES "^SunOS")
+ if(NOT CMAKE_HOST_SOLARIS)
# Avoid using CMAKE_SHARED_LIBRARY_C_FLAGS in version script checks on
# Solaris, because of an incompatibility with the Solaris link editor.
list(APPEND CMAKE_REQUIRED_FLAGS ${CMAKE_SHARED_LIBRARY_C_FLAGS})
@@ -270,7 +270,7 @@
" HAVE_LD_VERSION_SCRIPT)
if(NOT HAVE_LD_VERSION_SCRIPT)
set(CMAKE_REQUIRED_FLAGS ${_SAVED_CMAKE_REQUIRED_FLAGS})
- if(NOT CMAKE_HOST_SYSTEM_NAME MATCHES "^SunOS")
+ if(NOT CMAKE_HOST_SOLARIS)
# Again, avoid using CMAKE_SHARED_LIBRARY_C_FLAGS in version script
# checks on Solaris.
list(APPEND CMAKE_REQUIRED_FLAGS ${CMAKE_SHARED_LIBRARY_C_FLAGS})
