diff --git a/configure b/configure
index 1759694..60e0f24 100644
--- a/configure
+++ b/configure
@@ -5365,12 +5365,12 @@ probe_cc(){
         _flags_filter=msvc_flags_link
         _ld_lib='%.lib'
         _ld_path='-libpath:'
-    elif VSLANG=1033 $_cc -nologo- 2>&1 | grep -q ^Microsoft || { $_cc -v 2>&1 | grep -q clang && $_cc -? > /dev/null 2>&1; }; then
+    elif VSLANG=1033 $_cc -nologo- 2>&1 | grep -qi Microsoft || { $_cc -v 2>&1 | grep -q clang && $_cc -? > /dev/null 2>&1; }; then
         _type=msvc
-        if VSLANG=1033 $_cc -nologo- 2>&1 | grep -q ^Microsoft; then
+        if VSLANG=1033 $_cc -nologo- 2>&1 | grep -qi Microsoft; then
             # Depending on the tool (cl.exe or link.exe), the version number
             # is printed on the first line of stderr or stdout
-            _ident=$(VSLANG=1033 $_cc 2>&1 | grep ^Microsoft | head -n1 | tr -d '\r')
+            _ident=$(VSLANG=1033 $_cc 2>&1 | grep -i Microsoft | head -n1 | tr -d '\r')
         else
             _ident=$($_cc --version 2>/dev/null | head -n1 | tr -d '\r')
         fi
@@ -5486,7 +5486,7 @@ if [ -z "$CC_DEPFLAGS" ] && [ "$dep_cc" != "$cc" ]; then
     DEPCXXFLAGS=$_flags $_cxxflags
 fi
 
-if VSLANG=1033 $ar 2>&1 | grep -q ^Microsoft; then
+if VSLANG=1033 $ar 2>&1 | grep -qi Microsoft; then
     arflags="-nologo"
     ar_o='-out:$@'
 elif $ar 2>&1 | grep -q "\[D\] "; then