diff -r a6f357c18ac6 -r c5a225d7228c make/project.xml
--- a/make/project.xml	Thu Oct 02 17:58:43 2025 +0200
+++ b/make/project.xml	Thu Oct 02 21:21:45 2025 +0200
@@ -89,6 +89,16 @@
         <test>test -z "$FEATURE_COVERAGE"</test>
     </dependency>
 
+    <dependency name="memrchr">
+        <test>$TOOLCHAIN_CC -o /dev/null make/test_memrchr.c</test>
+        <cflags>-DWITH_MEMRCHR</cflags>
+    </dependency>
+
+    <dependency name="memrchr">
+        <test>$TOOLCHAIN_CC -o /dev/null -D_GNU_SOURCE make/test_memrchr.c</test>
+        <cflags>-DWITH_MEMRCHR -DMEMRCHR_NEED_GNU</cflags>
+    </dependency>
+
     <target>
         <feature name="api-docs">
             <dependencies>doxygen</dependencies>
@@ -106,6 +116,9 @@
             <desc>address sanitizer</desc>
             <dependencies>asan</dependencies>
         </feature>
+        <feature name="memrchr" default="true">
+            <dependencies>memrchr</dependencies>
+        </feature>
         <feature name="cxx-tests" default="true">
             <dependencies>cxx</dependencies>
             <desc>the check-cxx makefile target</desc>