Move includes outside of namespace (#5563)

Signed-off-by: Steffen Smolka <smolkaj@google.com>

Author: smolkaj

lib/exename.cpp

@@ -17,13 +17,11 @@ limitations under the License.
 #include "exename.h"
 
 #include <array>
+#include <climits>
 #include <cstring>
 #include <filesystem>
 #include <system_error>
 
-namespace P4 {
-
-#include <climits>
 #ifdef __APPLE__
 #include <unistd.h>
 
@@ -34,6 +32,8 @@ namespace P4 {
 #include <unistd.h>
 #endif
 
+namespace P4 {
+
 std::filesystem::path getExecutablePath() {
 #if defined(__APPLE__)
     std::array<char, PATH_MAX> buffer{};