Add full instructions for building OpenSSL locally

LibreSSL and BoringSSL remain TBD, but we should be able to work
with them in this framework.

Author: colmmacc

lib/Makefile

@@ -14,12 +14,12 @@
 #
 
 ifeq ($(shell uname),Darwin)
-    LIBS = -lc -lcrypto -lpthread
+    LIBS = -lc -lpthread
 else
-    LIBS = -lc -lcrypto -lpthread -lrt
+    LIBS = -lc -lpthread -lrt
 endif
 
-OBJS = $(wildcard ../utils/*.o ../stuffer/*.o ../tls/*.o ../iana/*.o ../crypto/*.o ../error/*.o)
+OBJS = $(wildcard ../utils/*.o ../stuffer/*.o ../tls/*.o ../iana/*.o ../crypto/*.o ../error/*.o ../libcrypto-root/lib/libcrypto.a)
 all: libs2n.a libs2n.so libs2n.dylib
 
 include ../s2n.mk

libcrypto-build/README.md

@@ -0,0 +1,4 @@
+This directory is used to store build artifacts (tarballs and source) for a locally
+built copy of libcrypto, either from OpenSSL, LibreSSL or BoringSSL.
+
+See the s2n [Usage Guide](https://github.com/awslabs/s2n/blob/master/docs/USAGE-GUIDE.md) for more details.

libcrypto-root/README.md

@@ -0,0 +1,3 @@
+This directory is used as the "prefix" target for a locally built copy
+of libcrypto. See the s2n [Usage Guide](https://github.com/awslabs/s2n/blob/master/docs/USAGE-GUIDE.md) for more details.
+

s2n.mk

@@ -19,8 +19,8 @@ INDENT  = $(shell (if indent --version 2>&1 | grep GNU > /dev/null; then echo in
 
 CFLAGS = -pedantic -Wall -Werror -Wimplicit -Wunused -Wcomment -Wchar-subscripts -Wuninitialized \
          -Wshadow -Wcast-qual -Wcast-align -Wwrite-strings -Wstack-protector -fPIC \
-         -std=c99 -D_POSIX_C_SOURCE=200112L -fstack-protector-all -O2 -I../api/ -I../ \
-         -Wno-deprecated-declarations -Wno-unknown-pragmas -Wformat-security \
+         -std=c99 -D_POSIX_C_SOURCE=200112L -fstack-protector-all -O2 -I../libcrypto-root/include/ \
+         -I../api/ -I../ -Wno-deprecated-declarations -Wno-unknown-pragmas -Wformat-security \
          -D_FORTIFY_SOURCE=2
 
 INDENTOPTS = -npro -kr -i4 -ts4 -nut -sob -l180 -ss -ncs -cp1

tests/unit/Makefile

@@ -23,14 +23,14 @@ include ../../s2n.mk
 CRUFT += $(wildcard *_test)
 
 ifeq ($(shell uname),Darwin)
-    LIBS = -lcrypto -lpthread -lm
+    LIBS = -lpthread -lm
 else
-    LIBS = -lcrypto -lpthread -lm -lrt
+    LIBS = -lpthread -lm -lrt
 endif
 
 # Suppress the unreachable code warning, because tests involve what should be
 # unreachable code
-CFLAGS += -Wno-unreachable-code -I../../ -I../../api/
+CFLAGS += -Wno-unreachable-code -I../../libcrypto-root/include/ -I../../ -I../../api/
 LDFLAGS += -L../../lib/ -L../testlib/ -ltests2n -ls2n ${LIBS}
 
 run_tests: build_tests