diff --git a/src/conf.h b/src/conf.h
index 1adde8fe..cd9dffa1 100644
--- a/src/conf.h
+++ b/src/conf.h
@@ -111,6 +111,7 @@ ACC_COMPILE_TIME_ASSERT_HEADER((char)(-1) == 255) // -funsigned-char
 
 #undef snprintf
 #undef vsnprintf
+#define HAVE_STDINT_H 1
 #define ACC_WANT_ACC_INCD_H 1
 #define ACC_WANT_ACC_INCE_H 1
 #define ACC_WANT_ACC_LIB_H 1
@@ -738,7 +739,7 @@ unsigned membuffer_get_size(MemBuffer &mb);
 
 #include "util/xspan.h"
 
-//#define DOCTEST_CONFIG_DISABLE
+//#define DOCTEST_CONFIG_DISABLE 1
 #include <doctest/parts/doctest_fwd.h>
 
 // util/dt_check.cpp
diff --git a/src/p_lx_elf.cpp b/src/p_lx_elf.cpp
index 63f826e9..b647df12 100644
--- a/src/p_lx_elf.cpp
+++ b/src/p_lx_elf.cpp
@@ -6085,7 +6085,7 @@ Elf64_Sym const *PackLinuxElf64::elf_lookup(char const *name) const
                     do {
                         if (gashend <= hp) {
                             char msg[120]; snprintf(msg, sizeof(msg),
-                                "bad gnu_hash[%#zx]  head=%u",
+                                "bad gnu_hash[%#tx]  head=%u",
                                 hp - hasharr, hhead);
                             throwCantPack(msg);
                         }
diff --git a/src/util/dt_check.cpp b/src/util/dt_check.cpp
index 0acaedea..3e3c7780 100644
--- a/src/util/dt_check.cpp
+++ b/src/util/dt_check.cpp
@@ -32,6 +32,10 @@
 **************************************************************************/
 
 bool upx_doctest_check(int argc, char **argv) {
+#if defined(DOCTEST_CONFIG_DISABLE)
+    UNUSED(argc);
+    UNUSED(argv);
+#else
     bool minimal = true;   // only show failing tests
     bool duration = false; // show timings
     bool success = false;  // show all tests
@@ -66,6 +70,7 @@ bool upx_doctest_check(int argc, char **argv) {
     int r = context.run();
     if (context.shouldExit() || r != 0)
         return false;
+#endif
     return true;
 }
 
diff --git a/src/util/dt_impl.cpp b/src/util/dt_impl.cpp
index 219eb5ec..2c07ee7a 100644
--- a/src/util/dt_impl.cpp
+++ b/src/util/dt_impl.cpp
@@ -32,6 +32,11 @@
 #define DOCTEST_CONFIG_IMPLEMENT
 #define DOCTEST_CONFIG_NO_MULTITHREADING
 #define DOCTEST_CONFIG_NO_UNPREFIXED_OPTIONS
+#if defined(__MSDOS__) && defined(__DJGPP__)
+#define DOCTEST_CONFIG_NO_POSIX_SIGNALS
+#endif
+#if !defined(DOCTEST_CONFIG_DISABLE)
 #include <doctest/parts/doctest.cpp>
+#endif
 
 /* vim:set ts=4 sw=4 et: */
diff --git a/src/util/xspan.cpp b/src/util/xspan.cpp
index 97c95834..a7b35352 100644
--- a/src/util/xspan.cpp
+++ b/src/util/xspan.cpp
@@ -480,6 +480,7 @@ TEST_CASE("Span constness") {
 //
 **************************************************************************/
 
+#if !defined(DOCTEST_CONFIG_DISABLE)
 namespace {
 int my_memcmp_v1(SPAN_P(const void) a, SPAN_0(const void) b, size_t n) {
     if (b == nullptr)
@@ -499,6 +500,7 @@ int my_memcmp_v2(SPAN_P(const char) a, SPAN_0(const char) b, size_t n) {
     return memcmp(x, y, n);
 }
 } // namespace
+#endif
 
 TEST_CASE("PtrOrSpan") {
     static const char buf[4] = {0, 1, 2, 3};
diff --git a/src/util/xspan_fwd.h b/src/util/xspan_fwd.h
index 1c1f1684..6965cc57 100644
--- a/src/util/xspan_fwd.h
+++ b/src/util/xspan_fwd.h
@@ -283,7 +283,9 @@ inline C<T> operator-(const C<T> &a, const LE32 &v) {
 template <class T>
 typename std::enable_if<sizeof(T) == 1, upx_rsize_t>::type upx_safe_strlen(const C<T> &a) {
     // not fully checked, but can require at least 1 byte
-    return upx_safe_strlen(a.raw_bytes(1));
+    upx_rsize_t len = upx_safe_strlen(a.raw_bytes(1));
+    (void) a.raw_bytes(len + 1); // now can do a full check
+    return len;
 }
 
 #endif // UPX_VERSION_HEX