fix musl build

Author: magnusuMET

Diff for: CMakeLists.txt

@@ -876,9 +876,15 @@ ENDIF()
 # Check for the math library so it can be explicitly linked.
 IF(NOT WIN32)
   FIND_LIBRARY(HAVE_LIBM NAMES math m libm)
-  MESSAGE(STATUS "Found Math library: ${HAVE_LIBM}")
   IF(NOT HAVE_LIBM)
-    MESSAGE(FATAL_ERROR "Unable to find the math library.")
+    CHECK_FUNCTION_EXISTS(exp HAVE_LIBM_FUNC)
+    IF(NOT HAVE_LIBM_FUNC)
+        MESSAGE(FATAL_ERROR "Unable to find the math library.")
+    ELSE(NOT HAVE_LIBM_FUNC)
+        SET(HAVE_LIBM "")
+    ENDIF()
+  ELSE(NOT HAVE_LIBM)
+    MESSAGE(STATUS "Found Math library: ${HAVE_LIBM}")
   ENDIF()
 ENDIF()
 
@@ -1313,6 +1319,7 @@ CHECK_INCLUDE_FILE("string.h"  HAVE_STRING_H)
 CHECK_INCLUDE_FILE("winsock2.h" HAVE_WINSOCK2_H)
 CHECK_INCLUDE_FILE("ftw.h"  HAVE_FTW_H)
 CHECK_INCLUDE_FILE("libgen.h" HAVE_LIBGEN_H)
+CHECK_INCLUDE_FILE("execinfo.h" HAVE_EXECINFO_H)
 
 # Symbol Exists
 CHECK_SYMBOL_EXISTS(isfinite "math.h" HAVE_DECL_ISFINITE)

Diff for: config.h.cmake.in

@@ -388,6 +388,9 @@ are set when opening a binary file on Windows. */
 with zip */
 #cmakedefine HDF5_SUPPORTS_PAR_FILTERS 1
 
+/* if true, backtrace support will be used. */
+#cmakedefine HAVE_EXECINFO_H 1
+
 /* if true, include JNA bug fix */
 #cmakedefine JNA 1
 

Diff for: libhdf5/hdf5debug.c

@@ -5,7 +5,7 @@
 #include "config.h"
 #include <stdarg.h>
 #include <stdio.h>
-#if !defined _WIN32 && !defined __CYGWIN__
+#ifdef HAVE_EXECINFO_H
 #include <execinfo.h>
 #endif
 
@@ -15,14 +15,14 @@
 
 #define STSIZE 1000
 
-#if !defined _WIN32 && !defined __CYGWIN__
+#ifdef HAVE_EXECINFO_H
 static void* stacktrace[STSIZE];
 #endif
 
 int
 nch5breakpoint(int err)
 {
-#if !defined _WIN32 && !defined __CYGWIN__
+#ifdef HAVE_EXECINFO_H
     int count = 0;
     char** trace = NULL;
     int i;