fix macos (#42)

* upgrade doctest to 2.4.9, update makefile for new pedantic clang silliness

* update license

* exciting new clang warnings

* explicitly enable -wcoversion for gcc

LICENSE

@@ -1,3 +1,17 @@
+Nanocobs is dual-licensed under both the "Unlicense" and the
+"Zero-Clause BSD" (0BSD) licenses. The intent of this dual-licensing
+structure is to make nanocobs as consumable as possible in as many
+environments / countries / companies as possible without encumbering
+users.
+
+This license applies to all of the nanocobs source code, build code,
+and tests, with the explicit exception of doctest.h, which exists under
+its own license and is included in this repository.
+
+The text of the two licenses follows below:
+
+============================== UNLICENSE ==============================
+
 This is free and unencumbered software released into the public domain.
 
 Anyone is free to copy, modify, publish, use, compile, sell, or
@@ -21,4 +35,19 @@ OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 OTHER DEALINGS IN THE SOFTWARE.
 
-For more information, please refer to <https://unlicense.org>
+For more information, please refer to <http://unlicense.org>
+
+================================ 0BSD =================================
+
+Copyright (C) 2019 by Charles Nicholson <[email protected]>
+
+Permission to use, copy, modify, and/or distribute this software for
+any purpose with or without fee is hereby granted.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

Makefile

@@ -12,6 +12,10 @@ BUILD_DIR := build
 OBJS := $(SRCS:%=$(BUILD_DIR)/%.o)
 DEPS := $(OBJS:.o=.d)
 OS := $(shell uname)
+COMPILER_VERSION := $(shell $(CXX) --version)
+
+CFLAGS = --std=c99
+CXXFLAGS = --std=c++17
 
 CPPFLAGS += -MMD -MP -Os -g
 
@@ -29,13 +33,17 @@ endif
 
 CPPFLAGS += -Wall -Werror -Wextra
 
-ifeq ($(OS),Darwin)
-CPPFLAGS += -Weverything -Wno-poison-system-directories -Wno-format-pedantic
+ifneq '' '$(findstring clang,$(COMPILER_VERSION))'
+CPPFLAGS += -Weverything \
+			-Wno-poison-system-directories \
+			-Wno-format-pedantic \
+			-Wno-c++98-compat-bind-to-temporary-copy
+CFLAGS += -Wno-declaration-after-statement
+else
+CPPFLAGS += -Wconversion
 endif
 
 CPPFLAGS += -Wno-c++98-compat -Wno-padded
-CFLAGS = --std=c99
-CXXFLAGS = --std=c++17
 
 $(BUILD_DIR)/cobs_unittests: $(OBJS) $(BUILD_DIR)/cobs.c.o Makefile
 	$(CXX) $(LDFLAGS) $(LDFLAGS_SAN) $(OBJS) $(BUILD_DIR)/cobs.c.o -o $@