diff --git a/lib/xmlparse.c b/lib/xmlparse.c
index 0655e08..b308e67 100644
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -3,12 +3,11 @@
 */
 
 #include <stddef.h>
-#include <stdint.h>
 #include <string.h>                     /* memset(), memcpy() */
 #include <assert.h>
 #include <limits.h>                     /* UINT_MAX */
 
-#ifdef COMPILED_FROM_DSP
+#ifdef WIN32
 #define getpid GetCurrentProcessId
 #else
 #include <sys/time.h>                   /* gettimeofday() */
@@ -18,7 +17,7 @@
 
 #define XML_BUILDING_EXPAT 1
 
-#ifdef COMPILED_FROM_DSP
+#ifdef WIN32
 #include "winconfig.h"
 #elif defined(MACOS_CLASSIC)
 #include "macconfig.h"
@@ -28,7 +27,7 @@
 #include "watcomconfig.h"
 #elif defined(HAVE_EXPAT_CONFIG_H)
 #include <expat_config.h>
-#endif /* ndef COMPILED_FROM_DSP */
+#endif /* ndef WIN32 */
 
 #include "ascii.h"
 #include "expat.h"
@@ -701,7 +700,7 @@
 static unsigned long
 gather_time_entropy(void)
 {
-#ifdef COMPILED_FROM_DSP
+#ifdef WIN32
   FILETIME ft;
   GetSystemTimeAsFileTime(&ft); /* never fails */
   return ft.dwHighDateTime ^ ft.dwLowDateTime;
@@ -723,13 +722,13 @@
   /* Process ID is 0 bits entropy if attacker has local access
    * XML_Parser address is few bits of entropy if attacker has local access */
   const unsigned long entropy =
-      gather_time_entropy() ^ getpid() ^ (uintptr_t)parser;
+      gather_time_entropy() ^ getpid() ^ (unsigned long)parser;
 
   /* Factors are 2^31-1 and 2^61-1 (Mersenne primes M31 and M61) */
   if (sizeof(unsigned long) == 4) {
     return entropy * 2147483647;
   } else {
-    return entropy * 2305843009213693951;
+    return entropy * (unsigned long)2305843009213693951;
   }
 }
 
@@ -1728,14 +1727,17 @@
   }
 
   if (len > bufferLim - bufferEnd) {
-    int neededSize = len + (int)(bufferEnd - bufferPtr);
+#ifdef XML_CONTEXT_BYTES
+    int keep;
+#endif  /* defined XML_CONTEXT_BYTES */
+    /* Do not invoke signed arithmetic overflow: */
+    int neededSize = (int) ((unsigned)len + (unsigned)(bufferEnd - bufferPtr));
     if (neededSize < 0) {
       errorCode = XML_ERROR_NO_MEMORY;
       return NULL;
     }
 #ifdef XML_CONTEXT_BYTES
-    int keep = (int)(bufferPtr - buffer);
-
+    keep = (int)(bufferPtr - buffer);
     if (keep > XML_CONTEXT_BYTES)
       keep = XML_CONTEXT_BYTES;
     neededSize += keep;
@@ -1760,7 +1762,8 @@
       if (bufferSize == 0)
         bufferSize = INIT_BUFFER_SIZE;
       do {
-        bufferSize *= 2;
+        /* Do not invoke signed arithmetic overflow: */
+        bufferSize = (int) (2U * (unsigned) bufferSize);
       } while (bufferSize < neededSize && bufferSize > 0);
       if (bufferSize <= 0) {
         errorCode = XML_ERROR_NO_MEMORY;
@@ -1887,7 +1890,7 @@
 XML_GetCurrentByteIndex(XML_Parser parser)
 {
   if (eventPtr)
-    return parseEndByteIndex - (parseEndPtr - eventPtr);
+    return (XML_Index)(parseEndByteIndex - (parseEndPtr - eventPtr));
   return -1;
 }
 
@@ -4959,9 +4962,9 @@
 
 static enum XML_Error PTRCALL
 errorProcessor(XML_Parser parser,
-               const char *s,
-               const char *end,
-               const char **nextPtr)
+               const char *UNUSED_P(s),
+               const char *UNUSED_P(end),
+               const char **UNUSED_P(nextPtr))
 {
   return errorCode;
 }
@@ -6285,7 +6288,7 @@
   }
   if (pool->blocks && pool->start == pool->blocks->s) {
     BLOCK *temp;
-    int blockSize = (int)(pool->end - pool->start)*2;
+    int blockSize = (int)((unsigned)(pool->end - pool->start)*2U);
 
     if (blockSize < 0)
       return XML_FALSE;