docs: stop recommending meson compile

With meson-0.60, meson compile stopped working with some targets:

$ meson compile -C build update-man-rules
ERROR: Can't invoke target `update-man-rules`: ambiguous name. Add target type and/or path: `PATH/NAME:TYPE`

This is obviously a regression in meson, but based on a chat with the
maintainers, it seems that there's some disagreement as to whether 'meson
compile' is useful and how exactly it should work. Since we're already at
meson 0.60.3 and this hasn't been fixed, and people generally don't seem to
consider this an issue, let's return to documenting the usual practice of
'ninja -C build' that just works everywhere.

(Since nobody has raised any fuss in systemd, it means that people are
generally using the shorter form during development too. I only noticed
because I pasted a command from the release docs when preparing -rc1.)

1 files changed, 3 insertions, 3 deletions

diff --git a/README b/README
index 109c093a6c..60b7aae930 100644
--- a/README
+++ b/README
@@ -207,7 +207,7 @@ REQUIREMENTS:
         python-jinja2
         python-lxml (optional, required to build the indices)
         python >= 3.5
-        meson >= 0.53.2 (>= 0.54.0 is required to build with 'meson compile')
+        meson >= 0.53.2
         ninja
         gcc, awk, sed, grep, and similar tools
         clang >= 10.0, llvm >= 10.0 (optional, required to build BPF programs
@@ -225,7 +225,7 @@ REQUIREMENTS:
         polkit (optional)
 
         To build in directory build/:
-          meson setup build/ && meson compile -C build/
+          meson setup build/ && ninja -C build/
 
         Any configuration options can be specified as -Darg=value... arguments
         to meson. After the build directory is initially configured, meson will
@@ -235,7 +235,7 @@ REQUIREMENTS:
         their current values.
 
         Useful commands:
-          meson compile -v -C build/ some/target
+          ninja -C build -v some/target
           meson test -C build/
           sudo meson install -C build/
           DESTDIR=... meson install -C build/