fixed for g++10

Makefile.linux

@@ -20,7 +20,7 @@ else ifeq ($(shell expr match ${CXXVER} "4\.[7-9]"),3) # gcc 4.7 - 4.9
 else ifeq ($(shell expr match ${CXXVER} "[5-6]"),1) # gcc 5 - 6
 	NEEDED_CXXFLAGS += -std=c++11
 	LDLIBS = -latomic
-else ifeq ($(shell expr match ${CXXVER} "[7-9]\|1[0-9]"),2) # gcc >= 7
+else ifeq ($(shell expr match ${CXXVER} "[1,7-9]"),1) # gcc >= 7
 	NEEDED_CXXFLAGS += -std=c++17
 	LDLIBS = -latomic
 else # not supported

Makefile.mingw

@@ -9,7 +9,7 @@ LDFLAGS := ${LD_DEBUG} -Wl,-Bstatic -static-libgcc -static-libstdc++
 CXXVER := $(shell $(CXX) -dumpversion)
 ifeq ($(shell expr match ${CXXVER} "[4]\.[7-9]\|4\.1[0-9]\|[5-6]"),4) # gcc 4.7 - 6
 	NEEDED_CXXFLAGS += -std=c++11
-else ifeq ($(shell expr match ${CXXVER} "[7-9]\|1[0-9]"),2) # gcc >= 7
+else ifeq ($(shell expr match ${CXXVER} "[1,7-9]"),1) # gcc >= 7
 	NEEDED_CXXFLAGS += -std=c++17
 else # not supported
 $(error Compiler too old)