From 8b7bba682cdc1ce2ae1e99377f3cc36d06ba58bf Mon Sep 17 00:00:00 2001
From: Jean Pierre Cimalando <jp-dev@inbox.ru>
Date: Fri, 31 Jan 2020 23:24:22 +0100
Subject: [PATCH 1/2] Compatibility with CMake 3.5

---
 CMakeLists.txt       |  5 ++++-
 cmake/CheckIPO.cmake | 16 ++++++++++++++--
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index d61b3229..3bc982a5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2,7 +2,10 @@ if(WIN32)
 cmake_minimum_required (VERSION 3.15)
 cmake_policy(SET CMP0091 NEW)
 else()
-cmake_minimum_required (VERSION 3.11)
+cmake_minimum_required (VERSION 3.5)
+if (POLICY CMP0069)
+    cmake_policy(SET CMP0069 NEW)
+endif()
 endif()
 project (sfizz VERSION 0.2.0 LANGUAGES CXX C)
 set(PROJECT_DESCRIPTION "A library to load SFZ description files and use them to render music.")
diff --git a/cmake/CheckIPO.cmake b/cmake/CheckIPO.cmake
index c86d3c04..5b524df7 100644
--- a/cmake/CheckIPO.cmake
+++ b/cmake/CheckIPO.cmake
@@ -1,9 +1,21 @@
 # Added in CMake 3.9
+
+if (CMAKE_VERSION VERSION_LESS 3.9)
+    message (WARNING "\nIPO checks are only available on CMake 3.9 and later.")
+
+    set(ENABLE_LTO OFF CACHE BOOL "" FORCE)
+
+    function (SFIZZ_ENABLE_LTO_IF_NEEDED TARGET)
+    endfunction()
+
+    return()
+endif()
+
 include (CheckIPOSupported)
 check_ipo_supported (RESULT result OUTPUT output)
 
 if (CMAKE_SYSTEM_PROCESSOR STREQUAL armv7l)
-    set(ENABLE_LTO OFF)
+    set(ENABLE_LTO OFF CACHE BOOL "" FORCE)
 endif()
 
 if (result AND ENABLE_LTO AND CMAKE_BUILD_TYPE STREQUAL "Release")
@@ -14,7 +26,7 @@ else()
     else()
         message (WARNING "\nIPO was disabled or not in a Release build.")
     endif()
-    set (ENABLE_LTO OFF)
+    set(ENABLE_LTO OFF CACHE BOOL "" FORCE)
 endif()
 
 function (SFIZZ_ENABLE_LTO_IF_NEEDED TARGET)

From 4be918e50ff22ea669e2aa9a43d863519e3e15cb Mon Sep 17 00:00:00 2001
From: Jean Pierre Cimalando <jp-dev@inbox.ru>
Date: Fri, 31 Jan 2020 23:30:51 +0100
Subject: [PATCH 2/2] Add a forgotten condition with USE_LIBCPP

---
 cmake/SfizzConfig.cmake | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/cmake/SfizzConfig.cmake b/cmake/SfizzConfig.cmake
index afa43821..db138080 100644
--- a/cmake/SfizzConfig.cmake
+++ b/cmake/SfizzConfig.cmake
@@ -43,10 +43,12 @@ endfunction(SFIZZ_LINK_LIBSNDFILE)
 # If we build with Clang use libc++
 if (CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND NOT ANDROID)
     set(USE_LIBCPP ON CACHE BOOL "Use libc++ with clang")
-    add_compile_options(-stdlib=libc++)
-    # Presumably need the above for linking too, maybe other options missing as well
-    add_link_options(-stdlib=libc++)   # New command on CMake master, not in 3.12 release
-    add_link_options(-lc++abi)   # New command on CMake master, not in 3.12 release
+    if (USE_LIBCPP)
+        add_compile_options(-stdlib=libc++)
+        # Presumably need the above for linking too, maybe other options missing as well
+        add_link_options(-stdlib=libc++)   # New command on CMake master, not in 3.12 release
+        add_link_options(-lc++abi)   # New command on CMake master, not in 3.12 release
+    endif()
 endif()
 
 # Don't show build information when building a different project