chore: adding NIMFLAGS usage to readme (#2469)

Makefile

@@ -57,6 +57,7 @@ TARGET ?= prod
 
 ## Git version
 GIT_VERSION ?= $(shell git describe --abbrev=6 --always --tags)
+## Compilation parameters. If defined in the CLI the assignments won't be executed
 NIM_PARAMS := $(NIM_PARAMS) -d:git_version=\"$(GIT_VERSION)\"
 
 ## Heaptracker options

README.md

@@ -26,6 +26,10 @@ The standard developer tools, including a C compiler, GNU Make, Bash, and Git. M
 # You'll run `make update` after each `git pull` in the future to keep those submodules updated.
 make wakunode2
 
+# Build with custom compilation flags. Do not use NIM_PARAMS unless you know what you are doing.
+# Replace with your own flags
+make wakunode2 NIMFLAGS="-d:chronicles_colors:none -d:disableMarchNative"
+
 # Run with DNS bootstrapping
 ./build/wakunode2 --dns-discovery --dns-discovery-url=DNS_BOOTSTRAP_NODE_URL