CMake: Add custom FindIconv

Workaround for https://gitlab.kitware.com/cmake/cmake/-/issues/24695
This commit is contained in:
TellowKrinkle 2023-04-08 21:42:49 -05:00
parent aaedc2827d
commit eb6bf08170
1 changed files with 101 additions and 0 deletions

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CMake/FindIconv.cmake Normal file
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# Based on CMake's FindIconv.cmake
# Modified to prefer non-built-in iconv over the built-in one
# See https://gitlab.kitware.com/cmake/cmake/-/issues/24695 for details
# This file can be deleted once that issue has been closed and the fix has
# made it into a satisfactory number of cmake versions. FreeBSD is the only
# system known to hit this so far, so "satisfactory" can probably be defined
# as "enough that most FreeBSD users have a fixed cmake".
find_path(Iconv_INCLUDE_DIR
NAMES "iconv.h"
DOC "iconv include directory")
mark_as_advanced(Iconv_INCLUDE_DIR)
find_library(Iconv_LIBRARY
NAMES iconv libiconv
NAMES_PER_DIR
DOC "iconv library (if not in the C library)")
mark_as_advanced(Iconv_LIBRARY)
# iconv can only be provided in libc on a POSIX system.
if(UNIX AND (NOT Iconv_INCLUDE_DIR OR NOT Iconv_LIBRARY))
include(CMakePushCheckState)
include(CheckCXXSourceCompiles)
cmake_push_check_state(RESET)
# We always suppress the message here: Otherwise on supported systems
# not having iconv in their C library (e.g. those using libiconv)
# would always display a confusing "Looking for iconv - not found" message
set(CMAKE_FIND_QUIETLY TRUE)
# The following code will not work, but it's sufficient to see if it compiles.
# Note: libiconv will define the iconv functions as macros, so CheckSymbolExists
# will not yield correct results.
set(Iconv_IMPLICIT_TEST_CODE
"
#include <stddef.h>
#include <iconv.h>
int main() {
char *a, *b;
size_t i, j;
iconv_t ic;
ic = iconv_open(\"to\", \"from\");
iconv(ic, &a, &i, &b, &j);
iconv_close(ic);
}
"
)
check_cxx_source_compiles("${Iconv_IMPLICIT_TEST_CODE}" Iconv_IS_BUILT_IN)
cmake_pop_check_state()
if(Iconv_IS_BUILT_IN)
unset(Iconv_INCLUDE_DIR)
unset(Iconv_LIBRARY)
endif()
else()
set(Iconv_IS_BUILT_IN FALSE)
endif()
set(_Iconv_REQUIRED_VARS)
if(Iconv_IS_BUILT_IN)
set(_Iconv_REQUIRED_VARS _Iconv_IS_BUILT_IN_MSG)
set(_Iconv_IS_BUILT_IN_MSG "built in to C library")
else()
set(_Iconv_REQUIRED_VARS Iconv_LIBRARY Iconv_INCLUDE_DIR)
endif()
# NOTE: glibc's iconv.h does not define _LIBICONV_VERSION
if(Iconv_INCLUDE_DIR AND EXISTS "${Iconv_INCLUDE_DIR}/iconv.h")
file(STRINGS ${Iconv_INCLUDE_DIR}/iconv.h Iconv_VERSION_DEFINE REGEX "_LIBICONV_VERSION (.*)")
if(Iconv_VERSION_DEFINE MATCHES "(0x[A-Fa-f0-9]+)")
set(Iconv_VERSION_NUMBER "${CMAKE_MATCH_1}")
# encoding -> version number: (major<<8) + minor
math(EXPR Iconv_VERSION_MAJOR "${Iconv_VERSION_NUMBER} >> 8" OUTPUT_FORMAT HEXADECIMAL)
math(EXPR Iconv_VERSION_MINOR "${Iconv_VERSION_NUMBER} - (${Iconv_VERSION_MAJOR} << 8)" OUTPUT_FORMAT HEXADECIMAL)
math(EXPR Iconv_VERSION_MAJOR "${Iconv_VERSION_MAJOR}" OUTPUT_FORMAT DECIMAL)
math(EXPR Iconv_VERSION_MINOR "${Iconv_VERSION_MINOR}" OUTPUT_FORMAT DECIMAL)
set(Iconv_VERSION "${Iconv_VERSION_MAJOR}.${Iconv_VERSION_MINOR}")
endif()
unset(Iconv_VERSION_DEFINE)
unset(Iconv_VERSION_NUMBER)
endif()
include(FindPackageHandleStandardArgs)
find_package_handle_standard_args(Iconv
REQUIRED_VARS ${_Iconv_REQUIRED_VARS}
VERSION_VAR Iconv_VERSION)
if(Iconv_FOUND)
if(Iconv_IS_BUILT_IN)
set(Iconv_INCLUDE_DIRS "")
set(Iconv_LIBRARIES "")
else()
set(Iconv_INCLUDE_DIRS "${Iconv_INCLUDE_DIR}")
set(Iconv_LIBRARIES "${Iconv_LIBRARY}")
endif()
if(NOT TARGET Iconv::Iconv)
add_library(Iconv::Iconv INTERFACE IMPORTED)
set_property(TARGET Iconv::Iconv PROPERTY INTERFACE_INCLUDE_DIRECTORIES "${Iconv_INCLUDE_DIRS}")
set_property(TARGET Iconv::Iconv PROPERTY INTERFACE_LINK_LIBRARIES "${Iconv_LIBRARIES}")
endif()
endif()