Fix ddtrace.so execute bit for ExecSolib in all build paths

ExecSolib requires execute permission on ddtrace.so (execve fails with
EACCES without it). Several build paths were missing chmod +x:

- build-tracing.sh: add chmod +x to standalone_* .so files used by
  SSI packages and generate-final-artifact.sh
- link-tracing-extension.sh: add chmod +x to extensions_* .so files
  used by deb/rpm/tar.gz packages
- libdatadog/spawn_worker: best-effort chmod before execve to handle
  cases where PHP's make install uses mode 0644 (no execute bit)
- datadog-setup.php: unconditionally chmod +x installed .so files
  rather than depending on the source having execute bit

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

Author: cataphract

.gitlab/build-tracing.sh

@@ -31,6 +31,7 @@ fi
 switch-php "${PHP_VERSION}"
 make clean && make -j "${MAKE_JOBS}" static
 objcopy --compress-debug-sections tmp/build_extension/modules/ddtrace.so "standalone_$(uname -m)/ddtrace-${PHP_API}${suffix}.so"
+chmod +x "standalone_$(uname -m)/ddtrace-${PHP_API}${suffix}.so"
 cp -v tmp/build_extension/modules/ddtrace.a "extensions_$(uname -m)/ddtrace-${PHP_API}${suffix}.a"
 if [ "${PHP_VERSION}" = "7.0" ]; then
   cp -v tmp/build_extension/ddtrace.ldflags "ddtrace_$(uname -m)${suffix}.ldflags"
@@ -41,6 +42,7 @@ if [ "${suffix}" != "-alpine" ]; then
   switch-php "${PHP_VERSION}-debug"
   make clean && make -j "${MAKE_JOBS}" static
   objcopy --compress-debug-sections tmp/build_extension/modules/ddtrace.so "standalone_$(uname -m)/ddtrace-${PHP_API}${suffix}-debug.so"
+  chmod +x "standalone_$(uname -m)/ddtrace-${PHP_API}${suffix}-debug.so"
   cp -v tmp/build_extension/modules/ddtrace.a "extensions_$(uname -m)/ddtrace-${PHP_API}${suffix}-debug.a"
 fi
 
@@ -49,4 +51,5 @@ switch-php "${PHP_VERSION}-zts"
 rm -r tmp/build_extension
 make clean && make -j "${MAKE_JOBS}" static
 objcopy --compress-debug-sections tmp/build_extension/modules/ddtrace.so "standalone_$(uname -m)/ddtrace-${PHP_API}${suffix}-zts.so"
+chmod +x "standalone_$(uname -m)/ddtrace-${PHP_API}${suffix}-zts.so"
 cp -v tmp/build_extension/modules/ddtrace.a "extensions_$(uname -m)/ddtrace-${PHP_API}${suffix}-zts.a"

.gitlab/link-tracing-extension.sh

@@ -9,6 +9,7 @@ for archive in extensions_$(uname -m)/*.a; do
   (
     cc -shared -Wl,-whole-archive $archive -Wl,-no-whole-archive $(cat "ddtrace_$(uname -m)${suffix}.ldflags") "libddtrace_php_$(uname -m)${suffix}.a" -Wl,-soname -Wl,ddtrace.so -o ${archive%.a}.so
     objcopy --compress-debug-sections ${archive%.a}.so
+    chmod +x ${archive%.a}.so
   ) &
   pids+=($!)
 done

Cargo.lock

@@ -956,9 +956,9 @@ function safe_copy_extension($source, $destination)
 
     $tmpName = $destination . '.tmp';
     copy($source, $tmpName);
-    // Preserve execute permission from source: required for ExecSolib (the kernel
-    // execve's ddtrace.so directly to spawn the sidecar).
-    if (!IS_WINDOWS && is_executable($source)) {
+    // Add execute permission: required for ExecSolib (the kernel execve's ddtrace.so
+    // directly to spawn the sidecar). Safe to apply unconditionally to .so files.
+    if (!IS_WINDOWS) {
         chmod($tmpName, fileperms($tmpName) | 0111);
     }
     rename($tmpName, $destination);