configure: drop support for Visual Studio < 2013

this is a precursor to requiring toolchains to support c99

BUG=aomedia:111

Change-Id: Ic501ea074e738fe7870ce3f56fb6e87a509632fd
diff --git a/build/make/configure.sh b/build/make/configure.sh
index 8ab8cf5..1ff6cc1 100644
--- a/build/make/configure.sh
+++ b/build/make/configure.sh
@@ -964,12 +964,10 @@
           disable_feature multithread
           disable_feature unit_tests
           vs_version=${tgt_cc##vs}
-          if [ $vs_version -ge 12 ]; then
-            # MSVC 2013 doesn't allow doing plain .exe projects for ARM,
-            # only "AppContainerApplication" which requires an AppxManifest.
-            # Therefore disable the examples, just build the library.
-            disable_feature examples
-          fi
+          # MSVC 2013 doesn't allow doing plain .exe projects for ARM,
+          # only "AppContainerApplication" which requires an AppxManifest.
+          # Therefore disable the examples, just build the library.
+          disable_feature examples
           ;;
         rvct)
           CC=armcc
@@ -1231,20 +1229,6 @@
           AS=msvs
           msvs_arch_dir=x86-msvs
           vc_version=${tgt_cc##vs}
-          case $vc_version in
-            7|8|9|10)
-              echo "${tgt_cc} does not support avx/avx2, disabling....."
-              RTCD_OPTIONS="${RTCD_OPTIONS}--disable-avx --disable-avx2 "
-              soft_disable avx
-              soft_disable avx2
-              ;;
-          esac
-          case $vc_version in
-            7|8|9)
-              echo "${tgt_cc} omits stdint.h, disabling webm-io..."
-              soft_disable webm_io
-              ;;
-          esac
           ;;
       esac