README: Add cross and clang recipes
Add configure command line examples for cross-compiling, for
compiling with clang, and for cross-compiling with clang.
Signed-off-by: Andrew Jones <andrew.jones@linux.dev>
diff --git a/README.md b/README.md
index 2d6f7db..be07dc2 100644
--- a/README.md
+++ b/README.md
@@ -17,6 +17,28 @@
NOTE: GCC cross-compiler is required for [build on macOS](README.macOS.md).
+## Cross-compiling
+
+A cross compiler may be configured by specifying a cross prefix. For example,
+for arm64
+
+ ./configure --arch=arm64 --cross-prefix=aarch64-linux-gnu-
+ make
+
+## clang
+
+clang may be used as an alternative to gcc.
+
+ ./configure --cc=clang
+ make
+
+clang may also be used with cross binutils when cross-compiling. For example,
+for riscv64
+
+ ./configure --arch=riscv64 --cc=clang --cflags='--target=riscv64' \
+ --cross-prefix=riscv64-linux-gnu-
+ make
+
## Standalone tests
The tests can be built as standalone. To create and use standalone tests do:
