Fixed crash if initialization of EGL failed but was tried again later.

The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().

cmake/macros.cmake

@@ -0,0 +1,73 @@
+macro(SET_OPTION _NAME _DESC)
+  list(APPEND ALLOPTIONS ${_NAME})
+  if(${ARGC} EQUAL 3)
+    set(_DEFLT ${ARGV2})
+  else()
+    set(_DEFLT OFF)
+  endif()
+  option(${_NAME} ${_DESC} ${_DEFLT})
+endmacro()
+
+macro(DEP_OPTION _NAME _DESC _DEFLT _DEPTEST _FAILDFLT)
+  list(APPEND ALLOPTIONS ${_NAME})
+  cmake_dependent_option(${_NAME} ${_DESC} ${_DEFLT} ${_DEPTEST} ${_FAILDFLT})
+endmacro()
+
+macro(OPTION_STRING _NAME _DESC _VALUE)
+  list(APPEND ALLOPTIONS ${_NAME})
+  set(${_NAME} ${_VALUE} CACHE STRING "${_DESC}")
+  set(HAVE_${_NAME} ${_VALUE})
+ENDMACRO()
+
+# Message Output
+macro(MESSAGE_WARN _TEXT)
+  message(STATUS "*** WARNING: ${_TEXT}")
+endmacro()
+
+macro(MESSAGE_ERROR _TEXT)
+  message(FATAL_ERROR "*** ERROR: ${_TEXT}")
+endmacro()
+
+macro(MESSAGE_BOOL_OPTION _NAME _VALUE)
+  if(${_VALUE})
+    message(STATUS "  ${_NAME}:\tON")
+  else()
+    message(STATUS "  ${_NAME}:\tOFF")
+  endif()
+endmacro()
+
+macro(MESSAGE_TESTED_OPTION _NAME)
+  set(_REQVALUE ${${_NAME}})
+  set(_PAD " ")
+  if(${ARGC} EQUAL 2)
+    set(_PAD ${ARGV1})
+  endif()
+  if(NOT HAVE_${_NAME})
+    set(HAVE_${_NAME} OFF)
+  elseif("${HAVE_${_NAME}}" MATCHES "1|TRUE|YES|Y")
+    set(HAVE_${_NAME} ON)
+  endif()
+  message(STATUS "  ${_NAME}${_PAD}(Wanted: ${_REQVALUE}): ${HAVE_${_NAME}}")
+endmacro()
+
+macro(LISTTOSTR _LIST _OUTPUT)
+  if(${ARGC} EQUAL 3)
+    # prefix for each element
+    set(_LPREFIX ${ARGV2})
+  else()
+    set(_LPREFIX "")
+  endif()
+  # Do not use string(REPLACE ";" " ") here to avoid messing up list
+  # entries
+  foreach(_ITEM ${${_LIST}})
+    set(${_OUTPUT} "${_LPREFIX}${_ITEM} ${${_OUTPUT}}")
+  endforeach()
+endmacro()
+
+macro(CHECK_OBJC_SOURCE_COMPILES SOURCE VAR)
+  set(PREV_REQUIRED_DEFS "${CMAKE_REQUIRED_DEFINITIONS}")
+  set(CMAKE_REQUIRED_DEFINITIONS "-x objective-c ${PREV_REQUIRED_DEFS}")
+  CHECK_C_SOURCE_COMPILES(${SOURCE} ${VAR})
+  set(CMAKE_REQUIRED_DEFINITIONS "${PREV_REQUIRED_DEFS}")
+endmacro()
+