diff --git a/Source/kwsys/ProcessWin32.c b/Source/kwsys/ProcessWin32.c
index 0b43b4a2af..c1a566f4ad 100644
--- a/Source/kwsys/ProcessWin32.c
+++ b/Source/kwsys/ProcessWin32.c
@@ -666,14 +666,14 @@ int kwsysProcess_SetWorkingDirectory(kwsysProcess* cp, const char* dir)
   if (dir && dir[0]) {
     wchar_t* wdir = kwsysEncoding_DupToWide(dir);
     /* We must convert the working directory to a full path.  */
-    DWORD length = GetFullPathNameW(wdir, 0, 0, 0);
+    DWORD length = GetFullPathNameW(wdir, 0, NULL, NULL);
     if (length > 0) {
       wchar_t* work_dir = malloc(length * sizeof(wchar_t));
       if (!work_dir) {
         free(wdir);
         return 0;
       }
-      if (!GetFullPathNameW(wdir, length, work_dir, 0)) {
+      if (!GetFullPathNameW(wdir, length, work_dir, NULL)) {
         free(work_dir);
         free(wdir);
         return 0;
diff --git a/Source/kwsys/SystemTools.cxx b/Source/kwsys/SystemTools.cxx
index cb6d73b7c8..f690476824 100644
--- a/Source/kwsys/SystemTools.cxx
+++ b/Source/kwsys/SystemTools.cxx
@@ -59,9 +59,6 @@
 
 #include <cctype>
 #include <cerrno>
-#ifdef __QNX__
-#  include <malloc.h> /* for malloc/free on QNX */
-#endif
 #include <cstdio>
 #include <cstdlib>
 #include <cstring>
@@ -338,10 +335,9 @@ inline void Realpath(const std::string& path, std::string& resolved_path,
                      std::string* errorMessage = nullptr)
 {
   std::wstring tmp = KWSYS_NAMESPACE::Encoding::ToWide(path);
-  wchar_t* ptemp;
   wchar_t fullpath[MAX_PATH];
   DWORD bufferLen = GetFullPathNameW(
-    tmp.c_str(), sizeof(fullpath) / sizeof(fullpath[0]), fullpath, &ptemp);
+    tmp.c_str(), sizeof(fullpath) / sizeof(fullpath[0]), fullpath, nullptr);
   if (bufferLen < sizeof(fullpath) / sizeof(fullpath[0])) {
     resolved_path = KWSYS_NAMESPACE::Encoding::ToNarrow(fullpath);
     KWSYS_NAMESPACE::SystemTools::ConvertToUnixSlashes(resolved_path);
@@ -824,25 +820,14 @@ static int kwsysUnPutEnv(const std::string& env)
 #elif defined(__CYGWIN__) || defined(__GLIBC__)
 /* putenv("A") removes A from the environment.  It must not put the
    memory in the environment because it does not have any "=" syntax.  */
+
 static int kwsysUnPutEnv(const std::string& env)
 {
   int err = 0;
-  size_t pos = env.find('=');
-  size_t const len = pos == std::string::npos ? env.size() : pos;
-  size_t const sz = len + 1;
-  char local_buf[256];
-  char* buf = sz > sizeof(local_buf) ? (char*)malloc(sz) : local_buf;
-  if (!buf) {
-    return -1;
-  }
-  strncpy(buf, env.c_str(), len);
-  buf[len] = 0;
-  if (putenv(buf) < 0 && errno != EINVAL) {
+  std::string buf = env.substr(0, env.find('='));
+  if (putenv(&buf[0]) < 0 && errno != EINVAL) {
     err = errno;
   }
-  if (buf != local_buf) {
-    free(buf);
-  }
   if (err) {
     errno = err;
     return -1;