configure: Disable webm_io when target is VS 7/8/9.

libwebm now requires stdint.h, and the noted Visual Studio versions
omit it.

Change-Id: I7e5de131c357cb7a99c33452b2b623882817df0f

build/make/configure.sh

diff --git a/build/make/configure.sh b/build/make/configure.sh
index d888268..b4d6bc9 100644
--- a/build/make/configure.sh
+++ b/build/make/configure.sh
@@ -1187,6 +1187,12 @@
               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