[PATCH v3] gdb/README: Refactor where build requirements are explained

[Guinevere Larsen <guinevere@redhat.com>]

User la_mettrie on IRC mentioned that they were having difficulties
building GDB, and after some debugging, we figured out that they weren't
using GNU Make. This is in the final documentation, but considering that
it is not an obvious place to look, and the README mentions other build
requirements, so this seems like a pretty obvious oversight.

This commit also reworks the paragraph explaining the build requirements,
turning into its own section and listing the GMP and MPFR requirements,
and the section is placed before the installation section to ensure
users see it before running into trouble.
---
 gdb/README | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/gdb/README b/gdb/README
index 492b0891668..ef6bdb2f1e1 100644
--- a/gdb/README
+++ b/gdb/README
@@ -10,6 +10,15 @@ date release information, mailing list links and archives, etc.
 GDB's bug tracking data base can be found at
 http://www.gnu.org/software/gdb/bugs/
 
+Build Requirements
+==========================
+
+   GDB requires a C++17 compiler, an ISO C standard library, GNU
+Make, the GNU Multiple Precision Arithmetic Library (GMP), and the
+GNU Multiple Precision Floating-Point Reliable Libray.  The GDB
+remote server, GDBserver, builds with some non-ISO standard
+libraries - e.g. for Windows CE.
+
 Unpacking and Installation -- quick overview
 ==========================
 
@@ -82,13 +91,6 @@ list of options, invoke the subdirectory `configure', like:
    (Take note of how this differs from the invocation used to actually
 configure the build tree.)
 
-   GDB requires a C++17 compiler.  If you do not have a
-C++17 compiler for your system, you may be able to download and install
-the GNU CC compiler.  It is available via anonymous FTP from the
-directory `ftp://ftp.gnu.org/pub/gnu/gcc'.  GDB also requires an ISO
-C standard library.  The GDB remote server, GDBserver, builds with some
-non-ISO standard libraries - e.g. for Windows CE.
-
    GDB can optionally be built against various external libraries.
 These dependencies are described below in the "`configure options"
 section of this README.

base-commit: e4fe38115fea0a9f357527959893f18ca8d51a03
-- 
2.53.0