doc: clarify stdenv phase flag attributes

1 files changed, 3 insertions, 3 deletions

diff --git a/doc/stdenv/stdenv.chapter.md b/doc/stdenv/stdenv.chapter.md
index 03bb8a9ff790e..2b49f8b725e1b 100644
--- a/doc/stdenv/stdenv.chapter.md
+++ b/doc/stdenv/stdenv.chapter.md
@@ -831,7 +831,7 @@ Note that shell arrays cannot be passed through environment variables, so you ca
 
 ##### `buildFlags` / `buildFlagsArray` {#var-stdenv-buildFlags}
 
-A list of strings passed as additional flags to `make`. Like `makeFlags` and `makeFlagsArray`, but only used by the build phase.
+A list of strings passed as additional flags to `make`. Like `makeFlags` and `makeFlagsArray`, but only used by the build phase. Any build targets should be specified as part of the `buildFlags`.
 
 ##### `preBuild` {#var-stdenv-preBuild}
 
@@ -872,7 +872,7 @@ If unset, use `check` if it exists, otherwise `test`; if neither is found, do no
 
 ##### `checkFlags` / `checkFlagsArray` {#var-stdenv-checkFlags}
 
-A list of strings passed as additional flags to `make`. Like `makeFlags` and `makeFlagsArray`, but only used by the check phase.
+A list of strings passed as additional flags to `make`. Like `makeFlags` and `makeFlagsArray`, but only used by the check phase. Unlike with `buildFlags`, the `checkTarget` is automatically added to the `make` invocation in addition to any `checkFlags` specified.
 
 ##### `checkInputs` {#var-stdenv-checkInputs}
 
@@ -914,7 +914,7 @@ installTargets = "install-bin install-doc";
 
 ##### `installFlags` / `installFlagsArray` {#var-stdenv-installFlags}
 
-A list of strings passed as additional flags to `make`. Like `makeFlags` and `makeFlagsArray`, but only used by the install phase.
+A list of strings passed as additional flags to `make`. Like `makeFlags` and `makeFlagsArray`, but only used by the install phase. Unlike with `buildFlags`, the `installTargets` are automatically added to the `make` invocation in addition to any `installFlags` specified.
 
 ##### `preInstall` {#var-stdenv-preInstall}