updates READMEs re electrum-ecc

contrib/build-wine/README_windows.md

@@ -21,6 +21,10 @@ Run install (this should install most dependencies):
 
 ### 2. Install `libsecp256k1`
 
+[comment]: # (technically the dll should be put into site-packages/electrum_ecc/,
+but putting it into electrum/ also works because of the `os.add_dll_directory` call in
+electrum/__init__.py)
+
 [libsecp256k1](https://github.com/bitcoin-core/secp256k1) is a required dependency.
 This is a C library, which you need to compile yourself.
 Electrum needs a dll, named `libsecp256k1-0.dll` (or newer `libsecp256k1-*.dll`),

contrib/osx/README_macos.md

@@ -15,18 +15,23 @@ $ cd electrum
 $ git submodule update --init
 ```
 
-Run install (this should install most dependencies):
+### 2. Prepare for compiling libsecp256k1
+
+To be able to build the `electrum-ecc` package from source
+(which is pulled in when installing Electrum in the next step),
+you need:
+```
+$ brew install autoconf automake libtool coreutils
+```
+
+### 3. Install Electrum
+
+Run install (this should install the dependencies):
 ```
 $ python3 -m pip install --user -e ".[gui,crypto]"
 ```
 
-### 2. Install libsecp256k1
-```
-$ brew install autoconf automake libtool coreutils
-$ contrib/make_libsecp256k1.sh
-```
-
-### 3. Run electrum:
+### 4. Run electrum:
 ```
 $ ./run_electrum
 ```