build: Use AC_CHECK_DECLS/check_symbol_exists for getentropy

This assumes that getentropy is declared in sys/random.h.

Should fix issues on iOS. See #774.

CMakeLists.txt

@@ -141,7 +141,7 @@ check_function_exists(class HAVE_CLASS)
 check_include_files(dlfcn.h HAVE_DLFCN_H)
 check_library_exists(dl dlopen "" HAVE_DLOPEN)
 check_include_files(dl.h HAVE_DL_H)
-check_function_exists(getentropy HAVE_GETENTROPY)
+check_symbol_exists(getentropy "sys/random.h" HAVE_DECL_GETENTROPY)
 check_library_exists(history append_history "" HAVE_LIBHISTORY)
 check_library_exists(readline readline "" HAVE_LIBREADLINE)
 check_function_exists(mmap HAVE_MMAP)
@@ -152,7 +152,6 @@ check_include_files(poll.h HAVE_POLL_H)
 check_library_exists(dld shl_load "" HAVE_SHLLOAD)
 check_include_files(stdint.h HAVE_STDINT_H)
 check_include_files(sys/mman.h HAVE_SYS_MMAN_H)
-check_include_files(sys/random.h HAVE_SYS_RANDOM_H)
 check_include_files(sys/select.h HAVE_SYS_SELECT_H)
 check_include_files(sys/socket.h HAVE_SYS_SOCKET_H)
 

config.h.cmake.in

@@ -14,7 +14,7 @@
 #cmakedefine HAVE_DL_H 1
 
 /* Define to 1 if you have the `getentropy' function. */
-#cmakedefine HAVE_GETENTROPY 1
+#cmakedefine HAVE_DECL_GETENTROPY 1
 
 /* Define if history library is there (-lhistory) */
 #cmakedefine HAVE_LIBHISTORY 1
@@ -54,9 +54,6 @@
 /* Define to 1 if you have the <sys/mman.h> header file. */
 #cmakedefine HAVE_SYS_MMAN_H 1
 
-/* Define to 1 if you have the <sys/random.h> header file. */
-#cmakedefine HAVE_SYS_RANDOM_H 1
-
 /* Define to 1 if you have the <sys/select.h> header file. */
 #cmakedefine HAVE_SYS_SELECT_H 1
 

configure.ac

@@ -298,19 +298,22 @@ dnl
 dnl Checks for header files.
 dnl
 AC_CHECK_HEADERS([stdint.h])
-AC_CHECK_HEADERS([sys/mman.h sys/random.h])
+AC_CHECK_HEADERS([sys/mman.h])
 AC_CHECK_HEADERS([dl.h dlfcn.h])
 AC_CHECK_HEADERS([glob.h])
 AM_CONDITIONAL(WITH_GLOB, test "$ac_cv_header_glob_h" = "yes")
 
 dnl Checks for library functions.
-AC_CHECK_FUNCS([getentropy mmap munmap])
+
+AC_CHECK_FUNCS([mmap munmap])
 
 AH_VERBATIM([HAVE_MUNMAP_AFTER],[/* mmap() is no good without munmap() */
 #if defined(HAVE_MMAP) && !defined(HAVE_MUNMAP)
 #  undef /**/ HAVE_MMAP
 #endif])
 
+AC_CHECK_DECLS([getentropy], [], [], [#include <sys/random.h>])
+
 dnl
 dnl Checks for inet libraries
 dnl

dict.c

@@ -929,11 +929,9 @@ xmlDictQLookup(xmlDictPtr dict, const xmlChar *prefix, const xmlChar *name) {
   #define WIN32_LEAN_AND_MEAN
   #include <windows.h>
   #include <bcrypt.h>
-#elif defined(HAVE_GETENTROPY)
+#elif HAVE_DECL_GETENTROPY
   #include <unistd.h>
-  #ifdef HAVE_SYS_RANDOM_H
-    #include <sys/random.h>
-  #endif
+  #include <sys/random.h>
 #else
   #include <time.h>
 #endif
@@ -962,7 +960,7 @@ xmlInitRandom(void) {
         if (!BCRYPT_SUCCESS(status))
             xmlAbort("libxml2: BCryptGenRandom failed with error code %lu\n",
                      GetLastError());
-#elif defined(HAVE_GETENTROPY)
+#elif HAVE_DECL_GETENTROPY
         while (1) {
             if (getentropy(globalRngState, sizeof(globalRngState)) == 0)
                 break;

meson.build

@@ -235,7 +235,6 @@ config_h.set_quoted('LOCALEDIR', dir_locale)
 xml_check_headers = [
     'stdint.h',
     'sys/mman.h',
-    'sys/random.h',
     'dl.h',
     'dlfcn.h',
     'glob.h',
@@ -258,14 +257,14 @@ endforeach
 # library functions
 xml_check_functions = [
     # fct             | header
-    ['getentropy', 'sys/random.h'],
-    ['mmap', 'sys/mman.h'],
-    ['munmap', 'sys/mman.h'],
+    ['getentropy', 'sys/random.h', 'HAVE_DECL_GETENTROPY'],
+    ['mmap', 'sys/mman.h', 'HAVE_MMAP'],
+    ['munmap', 'sys/mman.h', 'HAVE_MUNMAP'],
 ]
 
 foreach function : xml_check_functions
     if cc.has_header_symbol(function[1], function[0])
-        config_h.set10('HAVE_' + function[0].to_upper(), true)
+        config_h.set10(function[2], true)
     endif
 endforeach