Compile with C++2a

Will allow access to designated initializers.

Author: rbuchner-aril

Makefile.in

@@ -94,7 +94,7 @@ VPATH := $(addprefix $(src_dir)/, $(sprojs_enabled))
 # highest.
 
 default-CFLAGS   := -DPREFIX=\"$(prefix)\" -Wall -Wno-unused -Wno-nonportable-include-path -g -O2 -fPIC
-default-CXXFLAGS := $(default-CFLAGS) -std=c++17
+default-CXXFLAGS := $(default-CFLAGS) -std=c++2a
 
 mcppbs-CPPFLAGS := @CPPFLAGS@
 mcppbs-CFLAGS   := $(default-CFLAGS) @CFLAGS@