unix: Remove -Wdouble-promotion from main build, and 2 from coverage.

The 2 removed from coverage build are: -Wredundant-decls and
-Wstrict-prototypes.

unix/Makefile

@@ -19,7 +19,7 @@ INC += -I$(BUILD)
 
 # compiler settings
 CWARN = -Wall -Werror
-CWARN += -Wdouble-promotion -Wpointer-arith -Wuninitialized
+CWARN += -Wpointer-arith -Wuninitialized
 CFLAGS = $(INC) $(CWARN) -ansi -std=gnu99 -DUNIX $(CFLAGS_MOD) $(COPT) $(CFLAGS_EXTRA)
 
 # Debugging/Optimization
@@ -133,7 +133,7 @@ minimal:
 
 # build an interpreter for coverage testing and do the testing
 coverage:
-	$(MAKE) COPT="-O0" CFLAGS_EXTRA='-fprofile-arcs -ftest-coverage -Wdouble-promotion -Wformat -Wmissing-declarations -Wmissing-prototypes -Wold-style-definition -Wpointer-arith -Wredundant-decls -Wshadow -Wsign-compare -Wstrict-prototypes -Wuninitialized -Wunused-parameter' LDFLAGS_EXTRA='-fprofile-arcs -ftest-coverage' BUILD=build-coverage PROG=micropython_coverage
+	$(MAKE) COPT="-O0" CFLAGS_EXTRA='-fprofile-arcs -ftest-coverage -Wdouble-promotion -Wformat -Wmissing-declarations -Wmissing-prototypes -Wold-style-definition -Wpointer-arith -Wshadow -Wsign-compare -Wuninitialized -Wunused-parameter' LDFLAGS_EXTRA='-fprofile-arcs -ftest-coverage' BUILD=build-coverage PROG=micropython_coverage
 
 coverage_test: coverage
 	$(eval DIRNAME=$(notdir $(CURDIR)))