diff --git a/CMakeLists.txt b/CMakeLists.txt
index 738fc0a6..211cdda0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -31,7 +31,7 @@ if(NOT WIN32 AND NOT APPLE)
     set(GUI gtk2 CACHE STRING "GUI toolkit to use (one of: gtk2 gtk3)")
 endif()
 
-if(CMAKE_CXX_COMPILER_ID STREQUAL GNU)
+if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
     if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.0)
         # GCC 4.8/4.9 ship with broken but present <regex>. meh.
         message(FATAL_ERROR "GCC 5.0+ is required")
@@ -54,7 +54,7 @@ if(CMAKE_SYSTEM_NAME STREQUAL "Linux" OR CMAKE_SYSTEM_NAME STREQUAL "FreeBSD")
 endif()
 
 if(SANITIZE)
-    if(NOT (CMAKE_C_COMPILER_ID STREQUAL Clang AND CMAKE_CXX_COMPILER_ID STREQUAL Clang))
+    if(NOT (CMAKE_C_COMPILER_ID STREQUAL "Clang" AND CMAKE_CXX_COMPILER_ID STREQUAL "Clang"))
         message(ERROR "Sanitizers are only available in Clang/Clang++")
     endif()
     set(SANITIZE_FLAGS  "-O1 -fno-omit-frame-pointer -fno-optimize-sibling-calls")
@@ -166,9 +166,9 @@ if(MSVC)
     set(WARNING_FLAGS   "${WARNING_FLAGS} /we4062")
 endif()
 
-if(CMAKE_CXX_COMPILER_ID STREQUAL GNU OR CMAKE_CXX_COMPILER_ID STREQUAL Clang)
+if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU" OR CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
     set(WARNING_FLAGS   "-Wall -Wextra -Wno-unused-parameter")
-    if(CMAKE_CXX_COMPILER_ID STREQUAL Clang)
+    if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
         set(WARNING_FLAGS "${WARNING_FLAGS} -Wfloat-conversion")
     endif()
     # We rely on these -Werror flags.
diff --git a/cmake/DisableWarnings.cmake b/cmake/DisableWarnings.cmake
index 372e4408..b79ef9cd 100644
--- a/cmake/DisableWarnings.cmake
+++ b/cmake/DisableWarnings.cmake
@@ -1,15 +1,15 @@
 # Disables all warnings on MSVC and GNU-compatible compilers.
 
 function(disable_warnings)
-    if(CMAKE_C_COMPILER_ID STREQUAL GNU OR CMAKE_C_COMPILER_ID STREQUAL Clang)
+    if(CMAKE_C_COMPILER_ID STREQUAL "GNU" OR CMAKE_C_COMPILER_ID STREQUAL "Clang")
         set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -w" PARENT_SCOPE)
-    elseif(CMAKE_C_COMPILER_ID STREQUAL MSVC)
+    elseif(CMAKE_C_COMPILER_ID STREQUAL "MSVC")
         set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /W0" PARENT_SCOPE)
     endif()
 
-    if(CMAKE_CXX_COMPILER_ID STREQUAL GNU OR CMAKE_CXX_COMPILER_ID STREQUAL Clang)
+    if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU" OR CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
         set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -w" PARENT_SCOPE)
-    elseif(CMAKE_CXX_COMPILER_ID STREQUAL MSVC)
+    elseif(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC")
         set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W0" PARENT_SCOPE)
     endif()
 endfunction()