Revert "CDRIVER-4679 Prefer XSI-compliant strerror_r when available (mongodb#1350)"

This reverts commit ac436db.

Author: eramongodb

CMakeLists.txt

@@ -394,7 +394,7 @@ endif ()
 # Enable POSIX features up to POSIX.1-2008 plus the XSI extension and BSD-derived definitions.
 # Both _BSD_SOURCE and _DEFAULT_SOURCE are defined for backwards-compatibility with glibc 2.19 and earlier.
 # _BSD_SOURCE and _DEFAULT_SOURCE are required by `getpagesize`, `h_errno`, etc.
-# _XOPEN_SOURCE=700 is required by `strnlen`, `strerror_r`, etc.
+# _XOPEN_SOURCE=700 is required by `strnlen`, etc.
 add_definitions (-D_XOPEN_SOURCE=700 -D_BSD_SOURCE -D_DEFAULT_SOURCE)
 list (APPEND CMAKE_REQUIRED_DEFINITIONS -D_XOPEN_SOURCE=700 -D_BSD_SOURCE -D_DEFAULT_SOURCE)
 

src/libbson/CMakeLists.txt

@@ -14,14 +14,12 @@ include (MongoC-Warnings)
 
 set (BSON_OUTPUT_BASENAME "bson" CACHE STRING "Output bson library base name")
 
-include (CheckCSourceCompiles)
 include (CheckFunctionExists)
 include (CheckIncludeFile)
-include (CheckIncludeFiles)
 include (CheckStructHasMember)
 include (CheckSymbolExists)
-include (InstallRequiredSystemLibraries)
 include (TestBigEndian)
+include (InstallRequiredSystemLibraries)
 
 set (CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${PROJECT_SOURCE_DIR}/build/cmake)
 
@@ -85,6 +83,8 @@ else ()
    set (BSON_OS 1)
 endif ()
 
+include (CheckIncludeFiles)
+
 CHECK_INCLUDE_FILE (strings.h BSON_HAVE_STRINGS_H)
 if (NOT BSON_HAVE_STRINGS_H)
    set (BSON_HAVE_STRINGS_H 0)
@@ -119,38 +119,6 @@ else ()
    set (BSON_BYTE_ORDER 1234)
 endif ()
 
-# 1. Normally, `defined(_XOPEN_SOURCE) && _XOPEN_SOURCE >= 600` should be enough
-#    to detect if an XSI-compliant `strerror_r` is available.
-# 2. However, GNU provides an incompatible `strerror_r` as an extension,
-#    requiring an additional test for `!defined(_GNU_SOURCE)`.
-# 3. However, musl does not support the GNU extension even when `_GNU_SOURCE` is
-#    defined, preventing `!defined(_GNU_SOURCE)` from being a portable
-#    XSI-compliance test.
-# 4. However, musl does not provide a feature test macro to detect compilation
-#    with musl, and workarounds that use internal glibc feature test macros such
-#    as `defined(__USE_GNU)` are explicitly forbidden by glibc documentation.
-# 5. Therefore, give up on using feature test macros: use `CheckCSourceCompiles`
-#    to test if the current `strerror_r` is XSI-compliant if present.
-if (NOT WIN32)
-   CHECK_C_SOURCE_COMPILES(
-      [[
-         #include <string.h>
-         int test(int errnum, char *buf, size_t buflen) {
-            return strerror_r (errnum, buf, buflen);
-         }
-         int main(void) {}
-      ]]
-      BSON_HAVE_XSI_STRERROR_R
-      FAIL_REGEX "int-conversion"
-   )
-endif ()
-
-if (BSON_HAVE_XSI_STRERROR_R)
-   set(BSON_HAVE_XSI_STRERROR_R 1)
-else()
-   set(BSON_HAVE_XSI_STRERROR_R 0)
-endif ()
-
 configure_file (
    "${PROJECT_SOURCE_DIR}/src/bson/bson-config.h.in"
    "${PROJECT_BINARY_DIR}/src/bson/bson-config.h"

src/libbson/src/bson/bson-config.h.in

@@ -122,13 +122,4 @@
 # undef BSON_HAVE_STRLCPY
 #endif
 
-
-/*
- * Define to 1 if you have an XSI-compliant strerror_r on your platform.
- */
-#define BSON_HAVE_XSI_STRERROR_R @BSON_HAVE_XSI_STRERROR_R@
-#if BSON_HAVE_XSI_STRERROR_R != 1
-# undef BSON_HAVE_XSI_STRERROR_R
-#endif
-
 #endif /* BSON_CONFIG_H */

src/libbson/src/bson/bson-error.c

@@ -109,14 +109,12 @@ bson_strerror_r (int err_code,  /* IN */
    if (strerror_s (buf, buflen, err_code) != 0) {
       ret = buf;
    }
-#elif defined(BSON_HAVE_XSI_STRERROR_R)
+#elif defined(__GNUC__) && defined(_GNU_SOURCE)
+   ret = strerror_r (err_code, buf, buflen);
+#else /* XSI strerror_r */
    if (strerror_r (err_code, buf, buflen) == 0) {
       ret = buf;
    }
-#elif defined(_GNU_SOURCE)
-   ret = strerror_r (err_code, buf, buflen);
-#else
-   #error "Unable to find a supported strerror_r candidate"
 #endif
 
    if (!ret) {