Fix broken elif in dynamic.c
This fixes compilation in the following case:
$(MAKE) USE_OPENMP=1 USE_THREAD=1 NO_LAPACK=0 DYNAMIC_ARCH=1 \
DYNAMIC_LIST="HASWELL SKYLAKEX ATOM COOPERLAKE SAPPHIRERAPIDS ZEN"
@@ -96,7 +96,7 @@ extern gotoblas_t gotoblas_BARCELONA;
#endif
#ifdef DYN_ATOM
extern gotoblas_t gotoblas_ATOM;
-elif defined(DYN_NEHALEM)
+#elif defined(DYN_NEHALEM)
#define gotoblas_ATOM gotoblas_NEHALEM
#else
#define gotoblas_ATOM gotoblas_PRESCOTT
