diff --git a/core/BUILD b/core/BUILD
index ee3abf3..fe2909d 100644
--- a/core/BUILD
+++ b/core/BUILD
@@ -42,6 +42,9 @@ instrument_hooks_cflags = [
     "-Wno-unused-const-variable",
     "-Wno-type-limits",
     "-Wno-uninitialized",
+    # Older Clang lacks -Wunterminated-string-initialization; tolerate the unknown flag.
+    "-Wno-unknown-warning-option",
+    "-Wno-unterminated-string-initialization",
     # When cross-compiling:
     "-Wno-constant-conversion",
     "-Wno-incompatible-pointer-types",
@@ -49,6 +52,7 @@ instrument_hooks_cflags = [
 ]
 
 instrument_hooks_cflags_windows = [
+    "/std:c11",
     "/wd4101",  # unreferenced local variable (equivalent to -Wno-unused-variable)
     "/wd4189",  # local variable is initialized but not referenced (equivalent to -Wno-unused-but-set-variable)
     "/wd4100",  # unreferenced formal parameter (equivalent to -Wno-unused-parameter)
@@ -66,8 +70,8 @@ cc_library(
     copts = select({
         ":windows_strict_warnings": ["/W4","/WX"] + instrument_hooks_cflags_windows,
         ":windows": instrument_hooks_cflags_windows,
-        ":strict_warnings_enabled": ["-Wall", "-Werror"] + instrument_hooks_cflags,
-        "//conditions:default": instrument_hooks_cflags,
+        ":strict_warnings_enabled": ["-std=c11", "-Wall", "-Werror"] + instrument_hooks_cflags,
+        "//conditions:default": ["-std=c11"] + instrument_hooks_cflags,
     }),
     visibility = ["//visibility:public"],
 )
diff --git a/core/CMakeLists.txt b/core/CMakeLists.txt
index 4ee7018..f0d5eb2 100644
--- a/core/CMakeLists.txt
+++ b/core/CMakeLists.txt
@@ -27,6 +27,13 @@ set(instrument_hooks_SOURCE_DIR ${instrument_hooks_repo_SOURCE_DIR})
 # Add the instrument_hooks library
 add_library(instrument_hooks STATIC ${instrument_hooks_SOURCE_DIR}/dist/core.c)
 
+# Pin C11: the Zig-generated core.c is rejected under C23 (e.g. GCC 15's default),
+# which mangles [[noreturn]] placement in the embedded zig.h.
+set_target_properties(
+    instrument_hooks
+    PROPERTIES C_STANDARD 11 C_STANDARD_REQUIRED ON
+)
+
 target_include_directories(
     instrument_hooks
     PUBLIC
@@ -47,6 +54,9 @@ if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
         -Wno-unused-const-variable
         -Wno-type-limits
         -Wno-uninitialized
+        # Older Clang lacks -Wunterminated-string-initialization; tolerate the unknown flag.
+        -Wno-unknown-warning-option
+        -Wno-unterminated-string-initialization
         # When cross-compiling:
         -Wno-constant-conversion
         -Wno-incompatible-pointer-types