fix: patch msc_find_lib.m4 for multiarch library detection

ModSecurity v3.0.15 refactored library detection to centralize hardcoded
architecture paths in build/msc_find_lib.m4. The ssdeep.m4 and pcre2.m4
files are now thin wrappers that delegate to MSC_CHECK_LIB.

Patch only msc_find_lib.m4 to replace 'i386-linux-gnu' with the actual
detected architecture. This fixes SSDEEP library detection on arm64 and
other non-x86 platforms.

Fixes: build failures on linux/arm64 and linux/i386

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: fzipi

nginx/Dockerfile

@@ -51,8 +51,7 @@ RUN set -eux; \
     git clone https://github.com/owasp-modsecurity/ModSecurity --branch "v${MODSEC3_VERSION}" --depth 1 --recursive; \
     cd ModSecurity; \
     ARCH=$(gcc -print-multiarch); \
-    sed -ie "s/i386-linux-gnu/${ARCH}/g" build/ssdeep.m4; \
-    sed -ie "s/i386-linux-gnu/${ARCH}/g" build/pcre2.m4; \
+    sed -ie "s/i386-linux-gnu/${ARCH}/g" build/msc_find_lib.m4; \
     ./build.sh; \
     ./configure ${MODSEC3_FLAGS}; \
     make -j$(nproc) install; \

nginx/Dockerfile-alpine

@@ -48,8 +48,7 @@ RUN set -eux; \
     git clone https://github.com/owasp-modsecurity/ModSecurity --branch "v${MODSEC3_VERSION}" --depth 1 --recursive; \
     cd ModSecurity; \
     ARCH=$(gcc -print-multiarch); \
-    sed -ie "s/i386-linux-gnu/${ARCH}/g" build/ssdeep.m4; \
-    sed -ie "s/i386-linux-gnu/${ARCH}/g" build/pcre2.m4; \
+    sed -ie "s/i386-linux-gnu/${ARCH}/g" build/msc_find_lib.m4; \
     ./build.sh; \
     ./configure ${MODSEC3_FLAGS}; \
     make -j$(nproc) install; \