depends: disable builtin rules and suffixes.
What the developer wrote
Authored by Dmitry Goncharov
depends: disable builtin rules and suffixes.
When there is no rule to build a target in the makefile, make looks
for a builtin rule.
When --no-builtin-rules is specified make no longer performs this lookup.
E.g. the following in an excerpt from make -d output.
Here, make looks for a rule to build 'all'.
Considering target file 'all'.
File 'all' does not exist.
Looking for an implicit rule for 'all'.
Trying pattern rule with stem 'all'.
Trying implicit prerequisite 'all.o'.
Trying pattern rule with stem 'all'.
Trying implicit prerequisite 'all.c'.
Trying pattern rule with stem 'all'.
Trying implicit prerequisite 'all.cc'.
Trying pattern rule with stem 'all'.
Trying implicit prerequisite 'all.C'.
Trying pattern rule with stem 'all'.
Trying implicit prerequisite 'all.cpp'.
Trying pattern rule with stem 'all'.
Trying implicit prerequisite 'all.p'.
Trying pattern rule with stem 'all'.
Trying implicit prerequisite 'all.f'.
...
Many more lines like this are omitted.
Because this build system does not use make builtin rules or suffixes,
there is no benefit in having builtin rules enabled.
There are 2 benefits in having builtin rules disabled.
1. Improves performance by eliminating redundant lookups.
2. Simplifies troubleshooting by reducing the output of make -d or
make -p.
What changed, and why it matters
This commit changes the Bitcoin Core dependency build system to tell GNU make to stop searching for built-in pattern rules (like automatically trying to compile a .c file into an .o file). This is purely a performance and debugging cleanup: builds run slightly faster and 'make -d' output is much shorter. There is no security relevance.
No security action needed. Treat as a normal build-system hygiene improvement.
Security signals we found
No strong security signals were identified.
Evidence from the diff
The patch adds MAKEFLAGS += –no-builtin-rules to depends/Makefile. This disables GNU make’s built-in suffix/pattern rules and suffixes for the dependency build. The depends build system defines all needed rules explicitly, so the built-in lookup is unnecessary. The change reduces make’s implicit-rule search space and shrinks debug output, but does not alter any build logic, compiler flags, source handling, or output artifacts.
Changed components
depends/MakefileInspect captured patch +2 / −0
diff --git a/depends/Makefile b/depends/Makefile
index ed54eac4..14069bc3 100644
--- a/depends/Makefile
+++ b/depends/Makefile
@@ -1,4 +1,6 @@
.NOTPARALLEL :
+# Disable builtin rules and suffixes.
+MAKEFLAGS += --no-builtin-rules
# Pattern rule to print variables, e.g. make print-top_srcdir
print-%: FORCE
Why this scored 15/100
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