Fix issue #64 (clang build fails due to `details/format.h` diagnostic pop without prior push)

include/spdlog/details/format.h

@@ -102,6 +102,7 @@ inline uint32_t clzll(uint64_t x) {
 #endif
 
 #ifdef __clang__
+# pragma clang diagnostic push
 # pragma clang diagnostic ignored "-Wdocumentation"
 #endif
 
@@ -174,7 +175,6 @@ inline uint32_t clzll(uint64_t x) {
 #endif
 
 namespace fmt {
-
 // Fix the warning about long long on older versions of GCC
 // that don't support the diagnostic pragma.
 FMT_GCC_EXTENSION typedef long long LongLong;
@@ -288,7 +288,6 @@ public:
 };
 
 namespace internal {
-
 // The number of characters to store in the MemoryBuffer object itself
 // to avoid dynamic memory allocation.
 enum { INLINE_BUFFER_SIZE = 500 };
@@ -1111,7 +1110,6 @@ public:
 struct FormatSpec;
 
 namespace internal {
-
 class FormatterBase {
 private:
     ArgList args_;