adapted from: https://git.alpinelinux.org/aports/tree/community/gsoap/musl-fixes.patch
with help from paper42

--- a/gsoap/stdsoap2.c
+++ b/gsoap/stdsoap2.c
@@ -5125,7 +5125,7 @@
     hostent = NULL;
     soap->errnum = h_errno;
   }
-#elif (!defined(_GNU_SOURCE) || (!(~_GNU_SOURCE+1) && !defined(_POSIX_C_SOURCE) && !defined(_XOPEN_SOURCE)) || _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600 || defined(__ANDROID__) || defined(FREEBSD) || defined(__FreeBSD__)) && !defined(SUN_OS) && defined(HAVE_GETHOSTBYNAME_R)
+#elif defined(LINUX) && defined(HAVE_GETHOSTBYNAME_R)
   while ((r = gethostbyname_r(addr, hostent, tmpbuf, tmplen, &hostent, &soap->errnum)) < 0)
   {
     if (tmpbuf != soap->tmpbuf)
--- a/gsoap/stdsoap2.cpp
+++ b/gsoap/stdsoap2.cpp
@@ -5092,7 +5092,7 @@
 {
 #if (defined(_AIX43) || defined(TRU64) || defined(HP_UX)) && defined(HAVE_GETHOSTBYNAME_R)
   struct hostent_data ht_data;
-#elif (!defined(_GNU_SOURCE) || (!(~_GNU_SOURCE+1) && !defined(_POSIX_C_SOURCE) && !defined(_XOPEN_SOURCE)) || _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600 || defined(__ANDROID__) || defined(FREEBSD) || defined(__FreeBSD__)) && defined(HAVE_GETHOSTBYNAME_R)
+#elif defined(LINUX) && defined(HAVE_GETHOSTBYNAME_R)
   int r;
   char *tmpbuf = soap->tmpbuf;
   size_t tmplen = sizeof(soap->tmpbuf);
@@ -5125,7 +5125,7 @@
     hostent = NULL;
     soap->errnum = h_errno;
   }
-#elif (!defined(_GNU_SOURCE) || (!(~_GNU_SOURCE+1) && !defined(_POSIX_C_SOURCE) && !defined(_XOPEN_SOURCE)) || _POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600 || defined(__ANDROID__) || defined(FREEBSD) || defined(__FreeBSD__)) && !defined(SUN_OS) && defined(HAVE_GETHOSTBYNAME_R)
+#elif defined(LINUX) && defined(HAVE_GETHOSTBYNAME_R)
   while ((r = gethostbyname_r(addr, hostent, tmpbuf, tmplen, &hostent, &soap->errnum)) < 0)
   {
     if (tmpbuf != soap->tmpbuf)
--- a/gsoap/stdsoap2.cpp
+++ b/gsoap/stdsoap2.cpp
@@ -22618,9 +22618,9 @@
   {
 #ifndef WIN32
 # ifdef HAVE_STRERROR_R
-#  if !defined(_GNU_SOURCE) || (!(~_GNU_SOURCE+1) && ((!defined(_POSIX_C_SOURCE) && !defined(_XOPEN_SOURCE)) || (_POSIX_C_SOURCE >= 200112L || _XOPEN_SOURCE >= 600)))
+# ifndef __GLIBC__
     err = strerror_r(err, soap->msgbuf, sizeof(soap->msgbuf)); /* XSI-compliant */
     if (err != 0)
       soap_strcpy(soap->msgbuf, sizeof(soap->msgbuf), "unknown error");
 #  else
     return strerror_r(err, soap->msgbuf, sizeof(soap->msgbuf)); /* GNU-specific */
 #  endif
