libvpx: use bsd-compatible sed expressions

third_party/libvpx/lint_config.sh

Index: third_party/libvpx/lint_config.sh
diff --git a/third_party/libvpx/lint_config.sh b/third_party/libvpx/lint_config.sh
index 1a6c96dfbb94f63973272f3367827374e20e05aa..a4fd382333d01a3165f4c7ee1969fdc221b55401 100755
--- a/third_party/libvpx/lint_config.sh
+++ b/third_party/libvpx/lint_config.sh
@@ -56,7 +56,7 @@ combined_config="$(echo "$combined_config" | grep -v ARCHITECTURE)"
 combined_config="$(echo "$combined_config" | grep -v DO1STROUNDING)"
 
 # Remove all spaces.
-combined_config="$(echo "$combined_config" | sed 's/[ \t]//g')"
+combined_config="$(echo "$combined_config" | sed 's/[[:space:]]//g')"
 
 # Remove #define in the header file.
 combined_config="$(echo "$combined_config" | sed 's/.*define//')"
@@ -67,7 +67,7 @@ combined_config="$(echo "$combined_config" | sed 's/equ//')" # rvds style
 combined_config="$(echo "$combined_config" | sed 's/\.set//')" # apple style
 
 # Remove %define in YASM ASM files.
-combined_config="$(echo "$combined_config" | sed 's/%define\s *//')" # yasm style
+combined_config="$(echo "$combined_config" | sed 's/%define[[:space:]]*//')"
 
 # Remove useless comma in gas style assembly file.
 combined_config="$(echo "$combined_config" | sed 's/,//')"