Revert LTO commits:

"CMakeLists.txt - add developer option for enabling LTO builds"
This reverts commit d301105bab79b136974c4ea0a8df9fa818fae4e4.

Revert "scripts/buildtests.sh - LTO build checking"
This reverts commit 0c5f95c54cba7a64871a548ae2eb9bfbf0ba3a23.

2 files changed, 22 insertions, 58 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index a8590fc0..d3a4c1da 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -33,10 +33,6 @@
 #  Default=false (build shared and static libs)
 #  Takes precedence over STATIC_ONLY
 #
-# -DENABLE_LTO_BUILD=[true|false]
-#  Build a link-time optimized version (requires gcc or clang)
-#  Default=false (do not build a link time optimized version)
-#
 # -DGOBJECT_INTROSPECTION=[true|false]
 #  Set to build GObject introspection "typelib" files
 #  Requires GObject Introspection development package v0.6.7 or higher
@@ -482,32 +478,6 @@ if("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Qunused-arguments")
 endif()
 
-########################################################
-
-option(WITH_CXX_BINDINGS "Build the C++ bindings." True)
-if(WITH_CXX_BINDINGS)
-  enable_language(CXX)
-  if(CMAKE_CXX_COMPILER)
-    add_definitions(-DWITH_CXX_BINDINGS)
-  else()
-    message(STATUS
-      "Warning: Building the C++ bindings is not possible since a C++ compiler could not be found. "
-      "Turning-off C++ bindings"
-    )
-    set(WITH_CXX_BINDINGS False)
-  endif()
-endif()
-add_feature_info(
-  "Option WITH_CXX_BINDINGS"
-  WITH_CXX_BINDINGS
-  "build the C++ bindings. Requires a C++ compiler"
-)
-
-#some test programs need to know if we are using 32-bit time
-if(SIZEOF_TIME_T EQUAL 4)
-  set(USE_32BIT_TIME_T TRUE)
-endif()
-
 ################ Developer Options #####################
 option(ABI_DUMPER "Build for abi-dumper." False)
 if(ABI_DUMPER)
@@ -570,34 +540,31 @@ if(THREAD_SANITIZER)
   endif()
 endif()
 
-option(ENABLE_LTO_BUILD "Build a link-time optimized version." False)
-if(ENABLE_LTO_BUILD)
-  if(CMAKE_COMPILER_IS_GNUCC)
-    include(CheckCCompilerFlag)
-    check_c_compiler_flag(-flto HAVE_CC_COMPILER_LTO)
-    if(HAVE_CC_COMPILER_LTO)
-      set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wlto-type-mismatch -flto -fuse-linker-plugin")
-      set(CMAKE_AR "gcc-ar")
-      set(CMAKE_RANLIB "gcc-ranlib")
-    else()
-      message(FATAL_ERROR
-        "Your C compiler ${CMAKE_C_COMPILER_ID} does not support the LTO building.")
-    endif()
-    if(WITH_CXX_BINDINGS AND CMAKE_COMPILER_IS_GNUCXX)
-      include(CheckCXXCompilerFlag)
-      check_cxx_compiler_flag(-flto HAVE_CXX_COMPILER_LTO)
-      if(HAVE_CXX_COMPILER_LTO)
-        set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wlto-type-mismatch -flto -fuse-linker-plugin")
-      else()
-        message(FATAL_ERROR
-          "Your C++ compiler ${CMAKE_CXX_COMPILER_ID} does not support LTO building.")
-      endif()
-    endif()
+########################################################
+
+option(WITH_CXX_BINDINGS "Build the C++ bindings." True)
+if(WITH_CXX_BINDINGS)
+  enable_language(CXX)
+  if(CMAKE_CXX_COMPILER)
+    add_definitions(-DWITH_CXX_BINDINGS)
   else()
-    message(FATAL_ERROR
-      "Build link-time optimization using a non-GCC compiler is currently not supported.")
+    message(STATUS
+      "Warning: Building the C++ bindings is not possible since a C++ compiler could not be found. "
+      "Turning-off C++ bindings"
+    )
+    set(WITH_CXX_BINDINGS False)
   endif()
 endif()
+add_feature_info(
+  "Option WITH_CXX_BINDINGS"
+  WITH_CXX_BINDINGS
+  "build the C++ bindings. Requires a C++ compiler"
+)
+
+#some test programs need to know if we are using 32-bit time
+if(SIZEOF_TIME_T EQUAL 4)
+  set(USE_32BIT_TIME_T TRUE)
+endif()
 
 ################# build subdirs ########################
 
diff --git a/scripts/buildtests.sh b/scripts/buildtests.sh
index d003972b..0bbc2d49 100755
--- a/scripts/buildtests.sh
+++ b/scripts/buildtests.sh
@@ -477,7 +477,6 @@ BDIR=""
 CMAKEOPTS="-DCMAKE_BUILD_TYPE=Debug -DGOBJECT_INTROSPECTION=False -DICAL_GLIB=False -DICAL_BUILD_DOCS=False"
 UUCCMAKEOPTS="$CMAKEOPTS -DCMAKE_DISABLE_FIND_PACKAGE_ICU=True"
 TZCMAKEOPTS="$CMAKEOPTS -DUSE_BUILTIN_TZDATA=True"
-LTOCMAKEOPTS="$CMAKEOPTS -DENABLE_LTO_BUILD=True"
 
 #Static code checkers
 KRAZY
@@ -494,7 +493,6 @@ CLANGTIDY test2builtin "$TZCMAKEOPTS"
 GCC_BUILD test1 ""
 GCC_BUILD test2 "$CMAKEOPTS"
 GCC_BUILD test3 "$UUCCMAKEOPTS"
-GCC_BUILD test4 "$LTOCMAKEOPTS"
 if (test "`uname -s`" = "Linux")
 then
     echo "Temporarily disable cross-compile tests"
@@ -508,7 +506,6 @@ GCC_BUILD test2builtin "$TZCMAKEOPTS"
 CLANG_BUILD test1 ""
 CLANG_BUILD test2 "$CMAKEOPTS"
 CLANG_BUILD test3 "$UUCCMAKEOPTS"
-#CLANG_BUILD test4 "$LTOCMAKEOPTS"
 if (test "`uname -s`" = "Linux")
 then
     echo "Temporarily disable cross-compile tests"