diff --git a/CMakeLists.txt b/CMakeLists.txt
index e2d40edd..97e65d6b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -523,15 +523,9 @@ endif()
 
 # extra sanity checks to detect incompatible C vs CXX settings
 if(NOT UPX_CONFIG_CMAKE_DISABLE_PLATFORM_CHECK)
-if(NOT ",${CMAKE_C_PLATFORM_ID}," STREQUAL ",${CMAKE_CXX_PLATFORM_ID},")
-    message(FATAL_ERROR "ERROR: CMAKE_C_PLATFORM_ID CMAKE_CXX_PLATFORM_ID mismatch")
-endif()
-if(NOT ",${CMAKE_C_COMPILER_ABI}," STREQUAL ",${CMAKE_CXX_COMPILER_ABI},")
-    message(FATAL_ERROR "ERROR: CMAKE_C_COMPILER_ABI CMAKE_CXX_COMPILER_ABI mismatch")
-endif()
-if(NOT ",${CMAKE_C_COMPILER_FRONTEND_VARIANT}," STREQUAL ",${CMAKE_CXX_COMPILER_FRONTEND_VARIANT},")
-    message(FATAL_ERROR "ERROR: CMAKE_C_COMPILER_FRONTEND_VARIANT CMAKE_CXX_COMPILER_FRONTEND_VARIANT mismatch")
-endif()
+    upx_platform_check_mismatch(CMAKE_C_PLATFORM_ID CMAKE_CXX_PLATFORM_ID)
+    upx_platform_check_mismatch(CMAKE_C_COMPILER_ABI CMAKE_CXX_COMPILER_ABI)
+    upx_platform_check_mismatch(CMAKE_C_COMPILER_FRONTEND_VARIANT CMAKE_CXX_COMPILER_FRONTEND_VARIANT)
 endif() # UPX_CONFIG_CMAKE_DISABLE_PLATFORM_CHECK
 
 upx_cmake_include_hook(9_finish)
diff --git a/misc/cmake/functions.cmake b/misc/cmake/functions.cmake
index 1e6b47dc..dc5d05ea 100644
--- a/misc/cmake/functions.cmake
+++ b/misc/cmake/functions.cmake
@@ -171,6 +171,18 @@ function(upx_cache_bool_vars) # ARGV
     endforeach()
 endfunction()
 
+function(upx_platform_check_mismatch var_name_1 var_name_2)
+    if(DEFINED ${var_name_1} OR DEFINED ${var_name_2})
+        if(NOT ",${${var_name_1}}," STREQUAL ",${${var_name_2}},")
+            if(UPX_CONFIG_DISABLE_WERROR)
+                message(WARNING "WARNING: '${var_name_1}' '${var_name_2}' mismatch")
+            else()
+                message(FATAL_ERROR "FATAL ERROR: '${var_name_1}' '${var_name_2}' mismatch")
+            endif()
+        endif()
+    endif()
+endfunction()
+
 #***********************************************************************
 # compilation flags
 #***********************************************************************
diff --git a/misc/scripts/run_cmake_config.sh b/misc/scripts/run_cmake_config.sh
index 3e8fa027..15b5eae3 100755
--- a/misc/scripts/run_cmake_config.sh
+++ b/misc/scripts/run_cmake_config.sh
@@ -4,36 +4,37 @@ set -e; set -o pipefail
 
 # Copyright (C) Markus Franz Xaver Johannes Oberhumer
 # assemble cmake config flags; useful for CI jobs
+# also see misc/make/Makefile-extra.mk
 
 cmake_config_flags=()
 
-add_flag() {
+__add_cmake_config() {
     [[ -z "${!1}" ]] || cmake_config_flags+=( -D$1="${!1}" )
 }
 
 # pass common CMake settings from environment to cmake
 for v in CMAKE_VERBOSE_MAKEFILE; do
-    add_flag $v
+    __add_cmake_config $v
 done
 # pass common CMake toolchain settings from environment to cmake
 for v in CMAKE_ADDR2LINE CMAKE_AR CMAKE_DLLTOOL CMAKE_LINKER CMAKE_NM CMAKE_OBJCOPY CMAKE_OBJDUMP CMAKE_RANLIB CMAKE_READELF CMAKE_STRIP CMAKE_TAPI; do
-    add_flag $v
+    __add_cmake_config $v
 done
 # pass common CMake LTO toolchain settings from environment to cmake (for use with "-flto")
 for v in CMAKE_C_COMPILER_AR CMAKE_C_COMPILER_RANLIB CMAKE_CXX_COMPILER_AR CMAKE_CXX_COMPILER_RANLIB; do
-    add_flag $v
+    __add_cmake_config $v
 done
 # pass common CMake cross compilation settings from environment to cmake
 for v in CMAKE_SYSTEM_NAME CMAKE_SYSTEM_PROCESSOR CMAKE_CROSSCOMPILING_EMULATOR; do
-    add_flag $v
+    __add_cmake_config $v
 done
 # pass UPX config options from environment to cmake; see CMakeLists.txt
 for v in UPX_CONFIG_DISABLE_GITREV UPX_CONFIG_DISABLE_SANITIZE UPX_CONFIG_DISABLE_WSTRICT UPX_CONFIG_DISABLE_WERROR UPX_CONFIG_DISABLE_SELF_PACK_TEST; do
-    add_flag $v
+    __add_cmake_config $v
 done
 # pass UPX extra compile options from environment to cmake; see CMakeLists.txt
 for v in UPX_CONFIG_EXTRA_COMPILE_OPTIONS_BZIP2 UPX_CONFIG_EXTRA_COMPILE_OPTIONS_UCL UPX_CONFIG_EXTRA_COMPILE_OPTIONS_UPX UPX_CONFIG_EXTRA_COMPILE_OPTIONS_ZLIB UPX_CONFIG_EXTRA_COMPILE_OPTIONS_ZSTD; do
-    add_flag $v
+    __add_cmake_config $v
 done
 
 exec "${CMAKE:-cmake}" $UPX_CMAKE_CONFIG_FLAGS "${cmake_config_flags[@]}" "$@"
diff --git a/src/check/dt_check.cpp b/src/check/dt_check.cpp
index b80c3d95..6c47409a 100644
--- a/src/check/dt_check.cpp
+++ b/src/check/dt_check.cpp
@@ -741,12 +741,14 @@ TEST_CASE("libc snprintf") {
     CHECK_EQ(strcmp(buf, "-6.0.0.0.0.0.0.0.6.ffffffffffffffff"), 0);
     snprintf(buf, sizeof(buf), "%d.%d.%d.%d.%d.%d.%d.%d.%d.%#jx", -7, 0, 0, 0, 0, 0, 0, 0, 7, um);
     CHECK_EQ(strcmp(buf, "-7.0.0.0.0.0.0.0.7.0xffffffffffffffff"), 0);
-    snprintf(buf, sizeof(buf), "%#x %#lx %#llx", 17u, 18ul, 19ull);
-    CHECK_EQ(strcmp(buf, "0x11 0x12 0x13"), 0);
-    snprintf(buf, sizeof(buf), "%#X %#lX %#llX", 20u, 21ul, 22ull);
-    CHECK_EQ(strcmp(buf, "0X14 0X15 0X16"), 0);
-    snprintf(buf, sizeof(buf), "%#06x %#06lx %#06llx", 23u, 24ul, 25ull);
-    CHECK_EQ(strcmp(buf, "0x0017 0x0018 0x0019"), 0);
+    snprintf(buf, sizeof(buf), "%#X %#lx %#llx", 26u, 27ul, 28ull);
+    CHECK_EQ(strcmp(buf, "0X1A 0x1b 0x1c"), 0);
+    snprintf(buf, sizeof(buf), "%#06x %#06lX %#06llx", 26u, 27ul, 28ull);
+    CHECK_EQ(strcmp(buf, "0x001a 0X001B 0x001c"), 0);
+    snprintf(buf, sizeof(buf), "%#6x %#6lx %#6llX", 26u, 27ul, 28ull);
+    CHECK_EQ(strcmp(buf, "  0x1a   0x1b   0X1C"), 0);
+    snprintf(buf, sizeof(buf), "%#-6X %#-6lx %#-6llx", 26u, 27ul, 28ull);
+    CHECK_EQ(strcmp(buf, "0X1A   0x1b   0x1c  "), 0);
 }
 
 #if 0
diff --git a/src/check/dt_cxxlib.cpp b/src/check/dt_cxxlib.cpp
index 8f7fb27c..c4ba68b8 100644
--- a/src/check/dt_cxxlib.cpp
+++ b/src/check/dt_cxxlib.cpp
@@ -131,7 +131,7 @@ TEST_CASE("libc++") {
     CHECK(v.end() - v.begin() == N);
     CHECK(&v[0] == &(*(v.begin())));
     // CHECK(&v[0] + N == &(*(v.end()))); // TODO later: is this legal??
-    // TODO later
+    // TODO later: make sure that this throws
 #if defined(_LIBCPP_HARDENING_MODE_DEBUG) &&                                                       \
     (_LIBCPP_HARDENING_MODE == _LIBCPP_HARDENING_MODE_DEBUG)
     CHECK_THROWS((void) &v[N]);
@@ -176,7 +176,7 @@ struct MyVType2 {
     UPX_CXX_DISABLE_ADDRESS(Self)
     UPX_CXX_DISABLE_NEW_DELETE(Self)
 };
-TEST_CASE("upx_cxx_disable") {
+TEST_CASE("UPX_CXX_DISABLE_xxx") {
     MyType1<char, int, 1> dummy1;
     MyType2<char, int, 2> dummy2;
     MyVType1<char, int, 1> vdummy1;
@@ -260,7 +260,7 @@ struct Z2_X2 : public X2 {
 // util
 **************************************************************************/
 
-TEST_CASE("Deleter") {
+TEST_CASE("upx::ObjectDeleter 1") {
     LE16 *o = nullptr; // object
     LE32 *a = nullptr; // array
     {
@@ -275,7 +275,7 @@ TEST_CASE("Deleter") {
     assert(a == nullptr);
 }
 
-TEST_CASE("Deleter") {
+TEST_CASE("upx::ObjectDeleter 2") {
     constexpr size_t N = 2;
     BE16 *o[N]; // multiple objects
     BE32 *a[N]; // multiple arrays
@@ -284,8 +284,10 @@ TEST_CASE("Deleter") {
         upx::ArrayDeleter<BE32 **> a_deleter{a, 0};
         for (size_t i = 0; i < N; i++) {
             o[i] = new BE16;
+            assert(o[i] != nullptr);
             o_deleter.count += 1;
             a[i] = New(BE32, 1 + i);
+            assert(a[i] != nullptr);
             a_deleter.count += 1;
         }
     }
@@ -295,7 +297,7 @@ TEST_CASE("Deleter") {
     }
 }
 
-TEST_CASE("ptr_static_cast") {
+TEST_CASE("upx::ptr_static_cast") {
     // check that we don't trigger any -Wcast-align warnings
     using upx::ptr_static_cast;
     void *vp = nullptr;
@@ -335,7 +337,7 @@ TEST_CASE("ptr_static_cast") {
     assert((ic == ptr_static_cast<const int *>(ic)));
 }
 
-TEST_CASE("noncopyable") {
+TEST_CASE("upx::noncopyable") {
     struct Test : private upx::noncopyable {
         int v = 1;
     };
@@ -458,7 +460,7 @@ struct TestTriBool {
 };
 } // namespace
 
-TEST_CASE("TriBool") {
+TEST_CASE("upx::TriBool") {
     using upx::TriBool, upx::tribool;
     static_assert(!tribool(false));
     static_assert(tribool(true));
diff --git a/src/help.cpp b/src/help.cpp
index 274543a5..d8ba6bbb 100644
--- a/src/help.cpp
+++ b/src/help.cpp
@@ -96,16 +96,18 @@ void show_usage(void) {
 
 namespace {
 struct PackerNames {
+    PackerNames() noexcept = default;
+    ~PackerNames() noexcept = default;
     struct Entry {
         const char *fname;
         const char *sname;
     };
-    Entry names[64];
-    size_t names_count;
-    const Options *o;
-    PackerNames() : names_count(0), o(nullptr) {}
+    static constexpr size_t MAX_NAMES = 64;
+    Entry names[MAX_NAMES];
+    size_t names_count = 0;
+    const Options *o = nullptr;
     void add(const PackerBase *pb) {
-        assert_noexcept(names_count < 64);
+        assert_noexcept(names_count < MAX_NAMES);
         names[names_count].fname = pb->getFullName(o);
         names[names_count].sname = pb->getName();
         names_count++;
diff --git a/src/util/membuffer.cpp b/src/util/membuffer.cpp
index 89036256..c0cdbb2f 100644
--- a/src/util/membuffer.cpp
+++ b/src/util/membuffer.cpp
@@ -320,12 +320,17 @@ TEST_CASE("MemBuffer global overloads") {
     CHECK_THROWS(set_le64(mb4, 0));
 }
 
-TEST_CASE("MemBuffer unused") {
+TEST_CASE("MemBuffer unused 1") {
     MemBuffer mb;
     CHECK(mb.raw_ptr() == nullptr);
     CHECK(mb.raw_size_in_bytes() == 0);
 }
 
+TEST_CASE("MemBuffer unused 2") {
+    MemBuffer mb;
+    (void) mb;
+}
+
 TEST_CASE("MemBuffer array access") {
     constexpr size_t N = 16;
     MemBuffer mb(N);
diff --git a/src/work.cpp b/src/work.cpp
index ed06250f..9bed93b2 100644
--- a/src/work.cpp
+++ b/src/work.cpp
@@ -29,6 +29,9 @@
 // dispatch. PackMaster by itself will instantiate a concrete subclass
 // of class PackerBase which then does the actual work.
 // And see p_com.cpp for a simple executable format.
+//
+// This file also has the burden to deal with all those pesky low-level
+// file handling issues.
 
 #define WANT_WINDOWS_LEAN_H 1 // _get_osfhandle, GetFileTime, SetFileTime
 #include "util/system_headers.h"
@@ -325,7 +328,7 @@ void do_one_file(const char *const iname, char *const oname) may_throw {
         }
     }
 
-    // handle command - actual work is here
+    // handle command - actual work starts HERE
     PackMaster pm(&fi, opt);
     if (opt->cmd == CMD_COMPRESS)
         pm.pack(&fo);