diff --git a/ci/travis/conda/muparser.patch b/ci/travis/conda/muparser.patch
new file mode 100644
index 000000000000..af94f61449d1
--- /dev/null
+++ b/ci/travis/conda/muparser.patch
@@ -0,0 +1,12 @@
+diff --git a/recipe/meta.yaml b/recipe/meta.yaml
+index d3bbc43..8bef37d 100644
+--- a/recipe/meta.yaml
++++ b/recipe/meta.yaml
+@@ -58,6 +58,7 @@ requirements:
+     - libwebp-base
+     - libxml2
+     - lz4-c
++    - muparser
+     - openssl
+     - pcre2
+     - proj
diff --git a/ci/travis/conda/setup.sh b/ci/travis/conda/setup.sh
index eb08b2531a5c..8d9d7217fc43 100755
--- a/ci/travis/conda/setup.sh
+++ b/ci/travis/conda/setup.sh
@@ -20,6 +20,7 @@ git clone  https://github.com/conda-forge/gdal-feedstock.git
 cd gdal-feedstock
 
 patch -p1 < ../ci/travis/conda/libgdal-adbc.patch
+patch -p1 < ../ci/travis/conda/muparser.patch
 
 cat > recipe/recipe_clobber.yaml <<EOL
 source:
diff --git a/frmts/gtiff/libtiff/tif_dir.c b/frmts/gtiff/libtiff/tif_dir.c
index 74baa76e73ee..f8c01c92151a 100644
--- a/frmts/gtiff/libtiff/tif_dir.c
+++ b/frmts/gtiff/libtiff/tif_dir.c
@@ -2207,7 +2207,7 @@ int TIFFSetSubDirectory(TIFF *tif, uint64_t diroff)
             _TIFFCleanupIFDOffsetAndNumberMaps(tif);
             tif->tif_curdir = 0; /* first directory of new chain */
             /* add this offset to new IFD list */
-            _TIFFCheckDirNumberAndOffset(tif, tif->tif_curdir, diroff);
+            retval = _TIFFCheckDirNumberAndOffset(tif, tif->tif_curdir, diroff);
         }
         /* To be able to return from SubIFD or custom-IFD to main-IFD */
         tif->tif_setdirectory_force_absolute = TRUE;
diff --git a/frmts/vrt/vrtdataset.cpp b/frmts/vrt/vrtdataset.cpp
index 2f3244f89e07..2ab37fea1f67 100644
--- a/frmts/vrt/vrtdataset.cpp
+++ b/frmts/vrt/vrtdataset.cpp
@@ -1066,17 +1066,17 @@ GDALDataset *VRTDataset::OpenVRTProtocol(const char *pszSpec)
                 bool bFound = false;
                 for (int j = 0; j < nSubdatasets && papszSubdatasets[j]; j += 2)
                 {
-                    const std::string osSubdatasetSource(
-                        strstr(papszSubdatasets[j], "=") + 1);
-                    if (osSubdatasetSource.empty())
+                    const char *pszEqual = strchr(papszSubdatasets[j], '=');
+                    if (!pszEqual)
                     {
                         CPLError(CE_Failure, CPLE_IllegalArg,
                                  "'sd_name:' failed to obtain "
                                  "subdataset string ");
                         return nullptr;
                     }
+                    const char *pszSubdatasetSource = pszEqual + 1;
                     GDALSubdatasetInfoH info =
-                        GDALGetSubdatasetInfo(osSubdatasetSource.c_str());
+                        GDALGetSubdatasetInfo(pszSubdatasetSource);
                     char *component =
                         info ? GDALSubdatasetInfoGetSubdatasetComponent(info)
                              : nullptr;
@@ -1088,7 +1088,7 @@ GDALDataset *VRTDataset::OpenVRTProtocol(const char *pszSpec)
                     if (bFound)
                     {
                         poSrcDS.reset(GDALDataset::Open(
-                            osSubdatasetSource.c_str(),
+                            pszSubdatasetSource,
                             GDAL_OF_RASTER | GDAL_OF_VERBOSE_ERROR,
                             aosAllowedDrivers.List(), aosOpenOptions.List(),
                             nullptr));
diff --git a/port/CMakeLists.txt b/port/CMakeLists.txt
index c77e5c6b8df8..1d566b461d57 100644
--- a/port/CMakeLists.txt
+++ b/port/CMakeLists.txt
@@ -337,9 +337,7 @@ if (NOT CMAKE_CROSSCOMPILING AND BUILD_VSIPRELOAD AND "${CMAKE_SYSTEM}" MATCHES
     add_library(vsipreload MODULE vsipreload.cpp)
     set_target_properties(vsipreload PROPERTIES PREFIX "")
     target_link_libraries(vsipreload PRIVATE $<TARGET_NAME:${GDAL_LIB_TARGET_NAME}> ${CMAKE_DL_LIBS})
-    if (CMAKE_VERSION VERSION_GREATER_EQUAL 3.16)
-      set_property(SOURCE vsipreload.cpp PROPERTY SKIP_UNITY_BUILD_INCLUSION ON)
-    endif ()
+    set_property(SOURCE vsipreload.cpp PROPERTY SKIP_UNITY_BUILD_INCLUSION ON)
 
     # For musl / Alpine
     foreach(_header IN ITEMS stdio.h fcntl.h unistd.h dirent.h sys/stat.h)