Switch Strategies: Only Set `-std=c++11` When Default is Older

diff --git a/contrib/pzstd/Makefile b/contrib/pzstd/Makefile
index 423be59d283caa1d25745117d9ce527109aa4ffa..e62f8e873c56177a7bb5a89008d18cdcb0b7f315 100644 (file)
--- a/contrib/pzstd/Makefile
+++ b/contrib/pzstd/Makefile
@@ -37,24 +37,11 @@ CFLAGS   += -Wno-deprecated-declarations
 PZSTD_INC  = -I$(ZSTDDIR) -I$(ZSTDDIR)/common -I$(PROGDIR) -I.
 GTEST_INC  = -isystem googletest/googletest/include
 
-# Select newest C++ standard available, minimum C++11
-ifeq ($(shell echo | $(CXX) -x c++ -Werror -std=c++23 -c - -o /dev/null 2>/dev/null && echo 1 || echo 0),1)
-PZSTD_CXX_STD := -std=c++23
-else
-ifeq ($(shell echo | $(CXX) -x c++ -Werror -std=c++20 -c - -o /dev/null 2>/dev/null && echo 1 || echo 0),1)
-PZSTD_CXX_STD := -std=c++20
-else
-ifeq ($(shell echo | $(CXX) -x c++ -Werror -std=c++17 -c - -o /dev/null 2>/dev/null && echo 1 || echo 0),1)
-PZSTD_CXX_STD := -std=c++17
-else
-ifeq ($(shell echo | $(CXX) -x c++ -Werror -std=c++14 -c - -o /dev/null 2>/dev/null && echo 1 || echo 0),1)
-PZSTD_CXX_STD := -std=c++14
-else
+# If default C++ version is older than C++11, explicitly set C++11, which is the
+# minimum required by the code.
+ifeq ($(shell echo "\043if __cplusplus < 201103L\n\043error\n\043endif" | $(CXX) -x c++ -Werror -c - -o /dev/null 2>/dev/null && echo 1 || echo 0),0)
 PZSTD_CXX_STD := -std=c++11
 endif
-endif
-endif
-endif
 
 PZSTD_CPPFLAGS  = $(PZSTD_INC)
 PZSTD_CCXXFLAGS =