move blackmagic sdk to a make variable

Makefile

@@ -2,18 +2,7 @@ CC = gcc
 CFLAGS = -g
 LDFLAGS = -lstdc++ -lpthread -ldl -g
 
-BMSDK = /usr/local/include
-
 UNAME_S := $(shell sh -c 'uname -s 2>/dev/null || echo not')
-ifeq ($(UNAME_S),Linux)
-	ifneq ("$(wildcard /home/linuxbrew/.linuxbrew/include/DeckLinkAPIDispatch.cpp)","")
-		BMSDK = /home/linuxbrew/.linuxbrew/include
-	else
-		ifneq ("$(wildcard ~/.linuxbrew/include/DeckLinkAPIDispatch.cpp)","")
-			BMSDK = ~/.linuxbrew/include
-		endif
-	endif
-endif
 ifeq ($(UNAME_S),Darwin)
 	LDFLAGS += -framework CoreFoundation
 endif

README.md

@@ -3,3 +3,19 @@
 A utility to facilitate deck control via Blackmagic SDK.
 
 maintainer: @dericed.
+
+## installation
+
+### via homebrew
+
+Homebrew is recommended to install deckcontrol:
+
+`brew install amiaopensource/amioas/deckcontrol`
+
+### to build from source
+
+The BMDSK variable must be set to the path of the Blackmagic Decklink SDK. The SDK is available at https://www.blackmagicdesign.com/support/ as "Desktop Video #{version} SDK".
+
+```
+make BMDSK=/path/to/decklink/sdk
+```