replace Ofast with O3

Author: perazz

src/fpm_compiler.F90

@@ -173,7 +173,7 @@ module fpm_compiler
     flag_intel_warn = " -warn all", &
     flag_intel_check = " -check all", &
     flag_intel_debug = " -O0 -g", &
-    flag_intel_opt = " -Ofast", &
+    flag_intel_opt = " -O3", &
     flag_intel_fp = " -fp-model precise -pc64", &
     flag_intel_align = " -align all", &
     flag_intel_limit = " -error-limit 1", &
@@ -190,7 +190,7 @@ module fpm_compiler
     flag_intel_warn_win = " /warn:all", &
     flag_intel_check_win = " /check:all", &
     flag_intel_debug_win = " /Od /Z7", &
-    flag_intel_opt_win = " /Ofast", &
+    flag_intel_opt_win = " /O3", &
     flag_intel_fp_win = " /fp:precise", &
     flag_intel_align_win = " /align:all", &
     flag_intel_limit_win = " /error-limit:1", &