diff --git a/config/env.ini b/config/env.ini
index f8e18f3c..4a13ac5a 100644
--- a/config/env.ini
+++ b/config/env.ini
@@ -102,8 +102,8 @@ CXX=${SPC_DEFAULT_CXX}
 AR=${SPC_DEFAULT_AR}
 LD=${SPC_DEFAULT_LD}
 ; default compiler flags, used in CMake toolchain file, openssl and pkg-config build
-SPC_DEFAULT_C_FLAGS="-fPIC -O3 -pipe -fno-plt -fno-semantic-interposition -fstack-clash-protection -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -ffunction-sections -fdata-sections"
-SPC_DEFAULT_CXX_FLAGS="${SPC_DEFAULT_C_FLAGS}"
+SPC_DEFAULT_CFLAGS="-fPIC -O3 -pipe -fno-plt -fno-semantic-interposition -fstack-clash-protection -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -ffunction-sections -fdata-sections"
+SPC_DEFAULT_CXX_FLAGS="${SPC_DEFAULT_CFLAGS}"
 SPC_DEFAULT_LD_FLAGS="-Wl,-z,relro -Wl,--as-needed -Wl,-z,now -Wl,-z,noexecstack -Wl,--gc-sections"
 ; upx executable path
 UPX_EXEC=${PKG_ROOT_PATH}/bin/upx
@@ -120,7 +120,7 @@ SPC_CMD_PREFIX_PHP_CONFIGURE="./configure --prefix= --with-valgrind=no --disable
 ; embed type for php, static (libphp.a) or shared (libphp.so)
 SPC_CMD_VAR_PHP_EMBED_TYPE="static"
 ; EXTRA_CFLAGS for `configure` and `make` php
-SPC_CMD_VAR_PHP_MAKE_EXTRA_CFLAGS="-g -fstack-protector-strong -fno-ident -fPIE -fvisibility=hidden -fvisibility-inlines-hidden ${SPC_DEFAULT_C_FLAGS}"
+SPC_CMD_VAR_PHP_MAKE_EXTRA_CFLAGS="-g -fstack-protector-strong -fno-ident -fPIE -fvisibility=hidden -fvisibility-inlines-hidden ${SPC_DEFAULT_CFLAGS}"
 ; EXTRA_CXXFLAGS for `configure` and `make` php
 SPC_CMD_VAR_PHP_MAKE_EXTRA_CXXFLAGS="-g -fstack-protector-strong -fno-ident -fPIE -fvisibility=hidden -fvisibility-inlines-hidden ${SPC_DEFAULT_CXX_FLAGS}"
 ; EXTRA_LDFLAGS for `make` php, can use -release to set a soname for libphp.so
@@ -142,8 +142,8 @@ CXX=${SPC_DEFAULT_CXX}
 AR=${SPC_DEFAULT_AR}
 LD=${SPC_DEFAULT_LD}
 ; default compiler flags, used in CMake toolchain file, openssl and pkg-config build
-SPC_DEFAULT_C_FLAGS="--target=${MAC_ARCH}-apple-darwin -O3 -fno-plt -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -ffunction-sections -fdata-sections"
-SPC_DEFAULT_CXX_FLAGS="${SPC_DEFAULT_C_FLAGS}"
+SPC_DEFAULT_CFLAGS="--target=${MAC_ARCH}-apple-darwin -O3 -fno-plt -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -ffunction-sections -fdata-sections"
+SPC_DEFAULT_CXX_FLAGS="${SPC_DEFAULT_CFLAGS}"
 SPC_DEFAULT_LD_FLAGS="-Wl,-dead_strip"
 ; phpmicro patches, for more info, see: https://github.com/easysoft/phpmicro/tree/master/patches
 SPC_MICRO_PATCHES=cli_checks,macos_iconv
@@ -158,7 +158,7 @@ SPC_CMD_PREFIX_PHP_CONFIGURE="./configure --prefix= --with-valgrind=no --disable
 ; embed type for php, static (libphp.a) or shared (libphp.dylib)
 SPC_CMD_VAR_PHP_EMBED_TYPE="static"
 ; EXTRA_CFLAGS for `configure` and `make` php
-SPC_CMD_VAR_PHP_MAKE_EXTRA_CFLAGS="-g -fstack-protector-strong -fpic -fpie -fvisibility=hidden -fvisibility-inlines-hidden -Werror=unknown-warning-option ${SPC_DEFAULT_C_FLAGS}"
+SPC_CMD_VAR_PHP_MAKE_EXTRA_CFLAGS="-g -fstack-protector-strong -fpic -fpie -fvisibility=hidden -fvisibility-inlines-hidden -Werror=unknown-warning-option ${SPC_DEFAULT_CFLAGS}"
 ; EXTRA_CXXFLAGS for `configure` and `make` php
 SPC_CMD_VAR_PHP_MAKE_EXTRA_CXXFLAGS="-g -fstack-protector-strong -fno-ident -fpie -fvisibility=hidden -fvisibility-inlines-hidden -Werror=unknown-warning-option ${SPC_DEFAULT_CXX_FLAGS}"
 ; EXTRA_LDFLAGS for `make` php, can use -release to set a soname for libphp.dylib
diff --git a/docs/en/guide/env-vars.md b/docs/en/guide/env-vars.md
index 2fc50a65..bb542593 100644
--- a/docs/en/guide/env-vars.md
+++ b/docs/en/guide/env-vars.md
@@ -51,6 +51,6 @@ without modifying the default `config/env.ini` file.
 SPC_CONCURRENCY=4
 
 [linux]
-SPC_DEFAULT_C_FLAGS="-O3"
+SPC_DEFAULT_CFLAGS="-O3"
 ```
 
diff --git a/docs/zh/guide/env-vars.md b/docs/zh/guide/env-vars.md
index cd0d4a1d..8709280d 100644
--- a/docs/zh/guide/env-vars.md
+++ b/docs/zh/guide/env-vars.md
@@ -46,6 +46,6 @@ SPC_CONCURRENCY=4 spc build:php "mbstring,pcntl" --build-cli
 SPC_CONCURRENCY=4
 
 [linux]
-SPC_DEFAULT_C_FLAGS="-O3"
+SPC_DEFAULT_CFLAGS="-O3"
 ```
 
diff --git a/src/Package/Library/libjxl.php b/src/Package/Library/libjxl.php
index 48e9a239..74b87907 100644
--- a/src/Package/Library/libjxl.php
+++ b/src/Package/Library/libjxl.php
@@ -34,7 +34,7 @@ class libjxl extends LibraryPackage
             );
 
         if ($toolchain instanceof ZigToolchain) {
-            $cflags = getenv('SPC_DEFAULT_C_FLAGS') ?: getenv('CFLAGS') ?: '';
+            $cflags = getenv('SPC_DEFAULT_CFLAGS') ?: getenv('CFLAGS') ?: '';
             $has_avx512 = str_contains($cflags, '-mavx512') || str_contains($cflags, '-march=x86-64-v4');
             if (!$has_avx512) {
                 $cmake->addConfigureArgs(
diff --git a/src/Package/Target/php/frankenphp.php b/src/Package/Target/php/frankenphp.php
index 4414af66..4c428623 100644
--- a/src/Package/Target/php/frankenphp.php
+++ b/src/Package/Target/php/frankenphp.php
@@ -81,7 +81,7 @@ trait frankenphp
         $libs = $config['libs'];
 
         // Go's gcc driver doesn't automatically link against -lgcov or -lrt. Ugly, but necessary fix.
-        if ((str_contains((string) getenv('SPC_DEFAULT_C_FLAGS'), '-fprofile') ||
+        if ((str_contains((string) getenv('SPC_DEFAULT_CFLAGS'), '-fprofile') ||
                 str_contains((string) getenv('SPC_CMD_VAR_PHP_MAKE_EXTRA_CFLAGS'), '-fprofile')) &&
             $toolchain instanceof GccNativeToolchain) {
             $cflags .= ' -Wno-error=missing-profile';
diff --git a/src/StaticPHP/Package/LibraryPackage.php b/src/StaticPHP/Package/LibraryPackage.php
index fccb84ce..15f8824f 100644
--- a/src/StaticPHP/Package/LibraryPackage.php
+++ b/src/StaticPHP/Package/LibraryPackage.php
@@ -124,8 +124,8 @@ class LibraryPackage extends Package
         // get environment variable
         $env = getenv($this->getSnakeCaseName() . '_CFLAGS') ?: '';
         // get default c flags
-        $arch_c_flags = getenv('SPC_DEFAULT_C_FLAGS') ?: '';
-        if (!empty(getenv('SPC_DEFAULT_C_FLAGS')) && !str_contains($env, $arch_c_flags)) {
+        $arch_c_flags = getenv('SPC_DEFAULT_CFLAGS') ?: '';
+        if (!empty(getenv('SPC_DEFAULT_CFLAGS')) && !str_contains($env, $arch_c_flags)) {
             $env .= ' ' . $arch_c_flags;
         }
         return trim($env);
diff --git a/src/StaticPHP/Runtime/Executor/UnixCMakeExecutor.php b/src/StaticPHP/Runtime/Executor/UnixCMakeExecutor.php
index 1ddacb03..ecf17693 100644
--- a/src/StaticPHP/Runtime/Executor/UnixCMakeExecutor.php
+++ b/src/StaticPHP/Runtime/Executor/UnixCMakeExecutor.php
@@ -267,7 +267,7 @@ class UnixCMakeExecutor extends Executor
         }
         $os = PHP_OS_FAMILY;
         $target_arch = arch2gnu(php_uname('m'));
-        $cflags = getenv('SPC_DEFAULT_C_FLAGS');
+        $cflags = getenv('SPC_DEFAULT_CFLAGS');
         $cc = getenv('CC');
         $cxx = getenv('CXX');
         $include = BUILD_INCLUDE_PATH;
diff --git a/src/StaticPHP/Toolchain/ZigToolchain.php b/src/StaticPHP/Toolchain/ZigToolchain.php
index e817abd7..23f1b92e 100644
--- a/src/StaticPHP/Toolchain/ZigToolchain.php
+++ b/src/StaticPHP/Toolchain/ZigToolchain.php
@@ -44,13 +44,13 @@ class ZigToolchain implements UnixToolchainInterface
     {
         GlobalEnvManager::addPathIfNotExists($this->getPath());
         f_passthru('ulimit -n 2048'); // zig opens extra file descriptors, so when a lot of extensions are built statically, 1024 is not enough
-        $cflags = getenv('SPC_DEFAULT_C_FLAGS') ?: '';
+        $cflags = getenv('SPC_DEFAULT_CFLAGS') ?: '';
         $cxxflags = getenv('SPC_DEFAULT_CXX_FLAGS') ?: '';
         $extraCflags = getenv('SPC_CMD_VAR_PHP_MAKE_EXTRA_CFLAGS') ?: '';
         $cflags = trim($cflags . ' -Wno-date-time');
         $cxxflags = trim($cxxflags . ' -Wno-date-time');
         $extraCflags = trim($extraCflags . ' -Wno-date-time');
-        GlobalEnvManager::putenv("SPC_DEFAULT_C_FLAGS={$cflags}");
+        GlobalEnvManager::putenv("SPC_DEFAULT_CFLAGS={$cflags}");
         GlobalEnvManager::putenv("SPC_DEFAULT_CXX_FLAGS={$cxxflags}");
         GlobalEnvManager::putenv("SPC_CMD_VAR_PHP_MAKE_EXTRA_CFLAGS={$extraCflags}");
         GlobalEnvManager::putenv('RANLIB=zig-ranlib');
@@ -61,7 +61,7 @@ class ZigToolchain implements UnixToolchainInterface
             $extra_libs = trim($extra_libs . ' -lunwind');
             GlobalEnvManager::putenv("SPC_EXTRA_LIBS={$extra_libs}");
         }
-        $cflags = getenv('SPC_DEFAULT_C_FLAGS') ?: getenv('CFLAGS') ?: '';
+        $cflags = getenv('SPC_DEFAULT_CFLAGS') ?: getenv('CFLAGS') ?: '';
         $has_avx512 = str_contains($cflags, '-mavx512') || str_contains($cflags, '-march=x86-64-v4');
         if (!$has_avx512) {
             $extra_vars = getenv('SPC_EXTRA_PHP_VARS') ?: '';